How can i set a default value in component to a Mat-select triggering (change)












0















Hello i am trying to set a default value in a mat-select with multiple options in the component.ts, and i am managing to do so, but when i set a default value programatically the method that is supposed to execute when the value changes, does not execute, unless i change the value manually, i'm using (change) directive trigger to the method, is there anything else that i can use? like another directive.



I´m using ngModel to set the default value at the moment, setting a value to object.attribute



<mat-select [compareWith]="compareBasic" id="object" name="object" 
[(ngModel)]="object.attribute" (change)="methodThatIWantToTrigger" class="full-width"
required> </mat-select>


I should have multiple options in the mat-select, but if there is only one option i want to select that value by default, and i need to know that value that is select in order to get some data from the database. i'm doing something like so:



if (this.array.length == 1){ // if it has only one option
this.object.attribute = this.array[0];
}


but this leads to some errors or fails.










share|improve this question





























    0















    Hello i am trying to set a default value in a mat-select with multiple options in the component.ts, and i am managing to do so, but when i set a default value programatically the method that is supposed to execute when the value changes, does not execute, unless i change the value manually, i'm using (change) directive trigger to the method, is there anything else that i can use? like another directive.



    I´m using ngModel to set the default value at the moment, setting a value to object.attribute



    <mat-select [compareWith]="compareBasic" id="object" name="object" 
    [(ngModel)]="object.attribute" (change)="methodThatIWantToTrigger" class="full-width"
    required> </mat-select>


    I should have multiple options in the mat-select, but if there is only one option i want to select that value by default, and i need to know that value that is select in order to get some data from the database. i'm doing something like so:



    if (this.array.length == 1){ // if it has only one option
    this.object.attribute = this.array[0];
    }


    but this leads to some errors or fails.










    share|improve this question



























      0












      0








      0








      Hello i am trying to set a default value in a mat-select with multiple options in the component.ts, and i am managing to do so, but when i set a default value programatically the method that is supposed to execute when the value changes, does not execute, unless i change the value manually, i'm using (change) directive trigger to the method, is there anything else that i can use? like another directive.



      I´m using ngModel to set the default value at the moment, setting a value to object.attribute



      <mat-select [compareWith]="compareBasic" id="object" name="object" 
      [(ngModel)]="object.attribute" (change)="methodThatIWantToTrigger" class="full-width"
      required> </mat-select>


      I should have multiple options in the mat-select, but if there is only one option i want to select that value by default, and i need to know that value that is select in order to get some data from the database. i'm doing something like so:



      if (this.array.length == 1){ // if it has only one option
      this.object.attribute = this.array[0];
      }


      but this leads to some errors or fails.










      share|improve this question
















      Hello i am trying to set a default value in a mat-select with multiple options in the component.ts, and i am managing to do so, but when i set a default value programatically the method that is supposed to execute when the value changes, does not execute, unless i change the value manually, i'm using (change) directive trigger to the method, is there anything else that i can use? like another directive.



      I´m using ngModel to set the default value at the moment, setting a value to object.attribute



      <mat-select [compareWith]="compareBasic" id="object" name="object" 
      [(ngModel)]="object.attribute" (change)="methodThatIWantToTrigger" class="full-width"
      required> </mat-select>


      I should have multiple options in the mat-select, but if there is only one option i want to select that value by default, and i need to know that value that is select in order to get some data from the database. i'm doing something like so:



      if (this.array.length == 1){ // if it has only one option
      this.object.attribute = this.array[0];
      }


      but this leads to some errors or fails.







      angular5 angular-material2






      share|improve this question















      share|improve this question













      share|improve this question




      share|improve this question








      edited Nov 22 '18 at 17:29







      coder Tester

















      asked Nov 22 '18 at 10:47









      coder Testercoder Tester

      538




      538
























          2 Answers
          2






          active

          oldest

          votes


















          1














          Since you have 2 way data binding with [(ngModel)] you can use (ngModelChange) instead of (change) . It fires when the value changes.
          this is stackblitz example






          share|improve this answer
























          • Thank you for the help tho, but it is also not working, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • Dcan you show the exact mat-select code part.or stackblitz uploaded one?

            – Asanka
            Nov 22 '18 at 11:28











          • i have made a new edit

            – coder Tester
            Nov 22 '18 at 11:37











          • Value should be => [value] and objcect.attribute should be "P" or "T" or "D" same type that bind to value

            – Asanka
            Nov 22 '18 at 11:43











          • Not object.attriburte in this case emitirGuia.tipoInterveniente

            – Asanka
            Nov 22 '18 at 11:46





















          0














          It's because mat-select has selectionChange event and it's only fired up when user change it




          Event emitted when the selected value has been changed by the user.
          (angular material docs)




          If you want to emit this selectionChange you would have to try with programatically fire event, but you should avoid it. Maybe you can call this method inside your code? Give us your use case, maybe there is a better way.



          EDIT



          Due to your use case, you could go with ChangeDetectorRef.detectChanges(), so basicly, if you set your default value and you want to be sure, that it is selected in UI you can do something like this. It's a bit hacky, but it will work.



          if (this.array.length == 1){ // if it has only one option
          this.object.attribute = this.array[0];
          // this will force to refresh value in mat-select
          this.cdr.detectChanges()
          // here you can call your `methodThatIWantToTrigger` becaucse the view is updated.
          }


          Also don't forget to add it in your constructor in component.ts and import it Change



          import { ChangeDetectorRef } from '@angular/core';    

          constructor(private cdr: ChangeDetectorRef) { }





          share|improve this answer


























          • i have tried selectionChange before, and it didnt work, i made some edits in my question

            – coder Tester
            Nov 22 '18 at 11:18











          • Of course it won't work. because "Event emitted when the selected value has been changed by the user.", but Asanka answer should help you.

            – Patryk Brejdak
            Nov 22 '18 at 11:21











          • Asanka answer also does not work, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • @coderTester check my edit

            – Patryk Brejdak
            Nov 22 '18 at 11:33











          • yes that is kinda what i am doing now, it works sure, but i dont think its the best way of doing it. Im here just to see if there is a better option, maybe there is not.

            – coder Tester
            Nov 22 '18 at 11:42













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          2 Answers
          2






          active

          oldest

          votes








          2 Answers
          2






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          1














          Since you have 2 way data binding with [(ngModel)] you can use (ngModelChange) instead of (change) . It fires when the value changes.
          this is stackblitz example






          share|improve this answer
























          • Thank you for the help tho, but it is also not working, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • Dcan you show the exact mat-select code part.or stackblitz uploaded one?

            – Asanka
            Nov 22 '18 at 11:28











          • i have made a new edit

            – coder Tester
            Nov 22 '18 at 11:37











          • Value should be => [value] and objcect.attribute should be "P" or "T" or "D" same type that bind to value

            – Asanka
            Nov 22 '18 at 11:43











          • Not object.attriburte in this case emitirGuia.tipoInterveniente

            – Asanka
            Nov 22 '18 at 11:46


















          1














          Since you have 2 way data binding with [(ngModel)] you can use (ngModelChange) instead of (change) . It fires when the value changes.
          this is stackblitz example






          share|improve this answer
























          • Thank you for the help tho, but it is also not working, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • Dcan you show the exact mat-select code part.or stackblitz uploaded one?

            – Asanka
            Nov 22 '18 at 11:28











          • i have made a new edit

            – coder Tester
            Nov 22 '18 at 11:37











          • Value should be => [value] and objcect.attribute should be "P" or "T" or "D" same type that bind to value

            – Asanka
            Nov 22 '18 at 11:43











          • Not object.attriburte in this case emitirGuia.tipoInterveniente

            – Asanka
            Nov 22 '18 at 11:46
















          1












          1








          1







          Since you have 2 way data binding with [(ngModel)] you can use (ngModelChange) instead of (change) . It fires when the value changes.
          this is stackblitz example






          share|improve this answer













          Since you have 2 way data binding with [(ngModel)] you can use (ngModelChange) instead of (change) . It fires when the value changes.
          this is stackblitz example







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 22 '18 at 11:12









          AsankaAsanka

          1,085416




          1,085416













          • Thank you for the help tho, but it is also not working, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • Dcan you show the exact mat-select code part.or stackblitz uploaded one?

            – Asanka
            Nov 22 '18 at 11:28











          • i have made a new edit

            – coder Tester
            Nov 22 '18 at 11:37











          • Value should be => [value] and objcect.attribute should be "P" or "T" or "D" same type that bind to value

            – Asanka
            Nov 22 '18 at 11:43











          • Not object.attriburte in this case emitirGuia.tipoInterveniente

            – Asanka
            Nov 22 '18 at 11:46





















          • Thank you for the help tho, but it is also not working, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • Dcan you show the exact mat-select code part.or stackblitz uploaded one?

            – Asanka
            Nov 22 '18 at 11:28











          • i have made a new edit

            – coder Tester
            Nov 22 '18 at 11:37











          • Value should be => [value] and objcect.attribute should be "P" or "T" or "D" same type that bind to value

            – Asanka
            Nov 22 '18 at 11:43











          • Not object.attriburte in this case emitirGuia.tipoInterveniente

            – Asanka
            Nov 22 '18 at 11:46



















          Thank you for the help tho, but it is also not working, the method is not getting triggered

          – coder Tester
          Nov 22 '18 at 11:24





          Thank you for the help tho, but it is also not working, the method is not getting triggered

          – coder Tester
          Nov 22 '18 at 11:24













          Dcan you show the exact mat-select code part.or stackblitz uploaded one?

          – Asanka
          Nov 22 '18 at 11:28





          Dcan you show the exact mat-select code part.or stackblitz uploaded one?

          – Asanka
          Nov 22 '18 at 11:28













          i have made a new edit

          – coder Tester
          Nov 22 '18 at 11:37





          i have made a new edit

          – coder Tester
          Nov 22 '18 at 11:37













          Value should be => [value] and objcect.attribute should be "P" or "T" or "D" same type that bind to value

          – Asanka
          Nov 22 '18 at 11:43





          Value should be => [value] and objcect.attribute should be "P" or "T" or "D" same type that bind to value

          – Asanka
          Nov 22 '18 at 11:43













          Not object.attriburte in this case emitirGuia.tipoInterveniente

          – Asanka
          Nov 22 '18 at 11:46







          Not object.attriburte in this case emitirGuia.tipoInterveniente

          – Asanka
          Nov 22 '18 at 11:46















          0














          It's because mat-select has selectionChange event and it's only fired up when user change it




          Event emitted when the selected value has been changed by the user.
          (angular material docs)




          If you want to emit this selectionChange you would have to try with programatically fire event, but you should avoid it. Maybe you can call this method inside your code? Give us your use case, maybe there is a better way.



          EDIT



          Due to your use case, you could go with ChangeDetectorRef.detectChanges(), so basicly, if you set your default value and you want to be sure, that it is selected in UI you can do something like this. It's a bit hacky, but it will work.



          if (this.array.length == 1){ // if it has only one option
          this.object.attribute = this.array[0];
          // this will force to refresh value in mat-select
          this.cdr.detectChanges()
          // here you can call your `methodThatIWantToTrigger` becaucse the view is updated.
          }


          Also don't forget to add it in your constructor in component.ts and import it Change



          import { ChangeDetectorRef } from '@angular/core';    

          constructor(private cdr: ChangeDetectorRef) { }





          share|improve this answer


























          • i have tried selectionChange before, and it didnt work, i made some edits in my question

            – coder Tester
            Nov 22 '18 at 11:18











          • Of course it won't work. because "Event emitted when the selected value has been changed by the user.", but Asanka answer should help you.

            – Patryk Brejdak
            Nov 22 '18 at 11:21











          • Asanka answer also does not work, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • @coderTester check my edit

            – Patryk Brejdak
            Nov 22 '18 at 11:33











          • yes that is kinda what i am doing now, it works sure, but i dont think its the best way of doing it. Im here just to see if there is a better option, maybe there is not.

            – coder Tester
            Nov 22 '18 at 11:42


















          0














          It's because mat-select has selectionChange event and it's only fired up when user change it




          Event emitted when the selected value has been changed by the user.
          (angular material docs)




          If you want to emit this selectionChange you would have to try with programatically fire event, but you should avoid it. Maybe you can call this method inside your code? Give us your use case, maybe there is a better way.



          EDIT



          Due to your use case, you could go with ChangeDetectorRef.detectChanges(), so basicly, if you set your default value and you want to be sure, that it is selected in UI you can do something like this. It's a bit hacky, but it will work.



          if (this.array.length == 1){ // if it has only one option
          this.object.attribute = this.array[0];
          // this will force to refresh value in mat-select
          this.cdr.detectChanges()
          // here you can call your `methodThatIWantToTrigger` becaucse the view is updated.
          }


          Also don't forget to add it in your constructor in component.ts and import it Change



          import { ChangeDetectorRef } from '@angular/core';    

          constructor(private cdr: ChangeDetectorRef) { }





          share|improve this answer


























          • i have tried selectionChange before, and it didnt work, i made some edits in my question

            – coder Tester
            Nov 22 '18 at 11:18











          • Of course it won't work. because "Event emitted when the selected value has been changed by the user.", but Asanka answer should help you.

            – Patryk Brejdak
            Nov 22 '18 at 11:21











          • Asanka answer also does not work, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • @coderTester check my edit

            – Patryk Brejdak
            Nov 22 '18 at 11:33











          • yes that is kinda what i am doing now, it works sure, but i dont think its the best way of doing it. Im here just to see if there is a better option, maybe there is not.

            – coder Tester
            Nov 22 '18 at 11:42
















          0












          0








          0







          It's because mat-select has selectionChange event and it's only fired up when user change it




          Event emitted when the selected value has been changed by the user.
          (angular material docs)




          If you want to emit this selectionChange you would have to try with programatically fire event, but you should avoid it. Maybe you can call this method inside your code? Give us your use case, maybe there is a better way.



          EDIT



          Due to your use case, you could go with ChangeDetectorRef.detectChanges(), so basicly, if you set your default value and you want to be sure, that it is selected in UI you can do something like this. It's a bit hacky, but it will work.



          if (this.array.length == 1){ // if it has only one option
          this.object.attribute = this.array[0];
          // this will force to refresh value in mat-select
          this.cdr.detectChanges()
          // here you can call your `methodThatIWantToTrigger` becaucse the view is updated.
          }


          Also don't forget to add it in your constructor in component.ts and import it Change



          import { ChangeDetectorRef } from '@angular/core';    

          constructor(private cdr: ChangeDetectorRef) { }





          share|improve this answer















          It's because mat-select has selectionChange event and it's only fired up when user change it




          Event emitted when the selected value has been changed by the user.
          (angular material docs)




          If you want to emit this selectionChange you would have to try with programatically fire event, but you should avoid it. Maybe you can call this method inside your code? Give us your use case, maybe there is a better way.



          EDIT



          Due to your use case, you could go with ChangeDetectorRef.detectChanges(), so basicly, if you set your default value and you want to be sure, that it is selected in UI you can do something like this. It's a bit hacky, but it will work.



          if (this.array.length == 1){ // if it has only one option
          this.object.attribute = this.array[0];
          // this will force to refresh value in mat-select
          this.cdr.detectChanges()
          // here you can call your `methodThatIWantToTrigger` becaucse the view is updated.
          }


          Also don't forget to add it in your constructor in component.ts and import it Change



          import { ChangeDetectorRef } from '@angular/core';    

          constructor(private cdr: ChangeDetectorRef) { }






          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited Nov 22 '18 at 11:30

























          answered Nov 22 '18 at 10:59









          Patryk BrejdakPatryk Brejdak

          1,025518




          1,025518













          • i have tried selectionChange before, and it didnt work, i made some edits in my question

            – coder Tester
            Nov 22 '18 at 11:18











          • Of course it won't work. because "Event emitted when the selected value has been changed by the user.", but Asanka answer should help you.

            – Patryk Brejdak
            Nov 22 '18 at 11:21











          • Asanka answer also does not work, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • @coderTester check my edit

            – Patryk Brejdak
            Nov 22 '18 at 11:33











          • yes that is kinda what i am doing now, it works sure, but i dont think its the best way of doing it. Im here just to see if there is a better option, maybe there is not.

            – coder Tester
            Nov 22 '18 at 11:42





















          • i have tried selectionChange before, and it didnt work, i made some edits in my question

            – coder Tester
            Nov 22 '18 at 11:18











          • Of course it won't work. because "Event emitted when the selected value has been changed by the user.", but Asanka answer should help you.

            – Patryk Brejdak
            Nov 22 '18 at 11:21











          • Asanka answer also does not work, the method is not getting triggered

            – coder Tester
            Nov 22 '18 at 11:24











          • @coderTester check my edit

            – Patryk Brejdak
            Nov 22 '18 at 11:33











          • yes that is kinda what i am doing now, it works sure, but i dont think its the best way of doing it. Im here just to see if there is a better option, maybe there is not.

            – coder Tester
            Nov 22 '18 at 11:42



















          i have tried selectionChange before, and it didnt work, i made some edits in my question

          – coder Tester
          Nov 22 '18 at 11:18





          i have tried selectionChange before, and it didnt work, i made some edits in my question

          – coder Tester
          Nov 22 '18 at 11:18













          Of course it won't work. because "Event emitted when the selected value has been changed by the user.", but Asanka answer should help you.

          – Patryk Brejdak
          Nov 22 '18 at 11:21





          Of course it won't work. because "Event emitted when the selected value has been changed by the user.", but Asanka answer should help you.

          – Patryk Brejdak
          Nov 22 '18 at 11:21













          Asanka answer also does not work, the method is not getting triggered

          – coder Tester
          Nov 22 '18 at 11:24





          Asanka answer also does not work, the method is not getting triggered

          – coder Tester
          Nov 22 '18 at 11:24













          @coderTester check my edit

          – Patryk Brejdak
          Nov 22 '18 at 11:33





          @coderTester check my edit

          – Patryk Brejdak
          Nov 22 '18 at 11:33













          yes that is kinda what i am doing now, it works sure, but i dont think its the best way of doing it. Im here just to see if there is a better option, maybe there is not.

          – coder Tester
          Nov 22 '18 at 11:42







          yes that is kinda what i am doing now, it works sure, but i dont think its the best way of doing it. Im here just to see if there is a better option, maybe there is not.

          – coder Tester
          Nov 22 '18 at 11:42




















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