Angular Validator - CompareRule

To specify the expression that the validated field must match, set the rule's comparisonTarget configuration option. Assign a function to this option. The validated value will be compared to the function's return value. The comparison will be performed by using the operator that is set for the comparisonType option.

View Demo

See Also

• Data Validation

The rule is valid if the validated value is equal to the return value of the comparisonTarget function.

Use the ComparisonOperator enum to specify this option when the widget is used as an ASP.NET MVC 5 Control or a DevExtreme-Based ASP.NET Core Control. This enum accepts the following values: Equal, NotEqual, StrictEqual, NotStrictEqual, GreaterThan, GreaterThanOrEqual, LessThan, and LessThanOrEqual.

An error message can be specified as follows:

• Hard-code the message

  jQuery

  index.js

  $(function() {
      $("#textBox").dxTextBox({ ... })
          .dxValidator({
              type: "compare",
              message: "My custom message"
          });
  });

  Angular

  app.component.html

  app.module.ts

  <dx-text-box> 
      <dx-validator>
          <dxi-validation-rule 
              type="compare" 
              message="My custom message">
          </dxi-validation-rule>
      </dx-validator>
  </dx-text-box>

  import { BrowserModule } from '@angular/platform-browser';
  import { NgModule } from '@angular/core';
  import { AppComponent } from './app.component';
  
  import { DxValidatorModule,
           DxTextBoxModule } from 'devextreme-angular';
  
  @NgModule({
      declarations: [
          AppComponent
      ],
      imports: [
          DxTextBoxModule,
          BrowserModule,
          DxValidatorModule
      ],
      providers: [],
      bootstrap: [AppComponent]
  })
  export class AppModule { }

  Vue

  App.vue

  <template>
      <DxTextBox>
          <DxValidator>
              <DxCompareRule
                  message="My custom message"
              />
          </DxValidator>
      </DxTextBox>
  </template>
  
  <script>
  import 'devextreme/dist/css/dx.common.css';
  import 'devextreme/dist/css/dx.light.css';
  
  import { DxTextBox } from 'devextreme-vue/text-box';
  import {
      DxValidator,
      DxCompareRule
  } from 'devextreme-vue/validator';
  
  export default {
      components: {
          DxTextBox,
          DxValidator,
          DxCompareRule
      }
  }
  </script>

  React

  App.js

  import React from 'react';
  
  import 'devextreme/dist/css/dx.common.css';
  import 'devextreme/dist/css/dx.light.css';
  
  import { TextBox } from 'devextreme-react/text-box';
  import {
      Validator,
      CompareRule
  } from 'devextreme-react/validator';
  
  class App extends React.Component {
      render() {
          return (
              <TextBox>
                  <Validator>
                      <CompareRule
                          message="My custom message" />
                  </Validator>
              </TextBox>
          );
      }
  }
  export default App;

• Hide the message

  jQuery

  index.js

  $(function() {
      $("#textBox").dxTextBox({ ... })
          .dxValidator({
              type: "compare",
              message: ""
          });
  });

  Angular

  app.component.html

  app.module.ts

  <dx-text-box>
      <dx-validator>
          <dxi-validation-rule 
              type="compare" 
              message="">
          </dxi-validation-rule>
      </dx-validator>
  </dx-text-box>

  import { BrowserModule } from '@angular/platform-browser';
  import { NgModule } from '@angular/core';
  import { AppComponent } from './app.component';
  
   import { DxValidatorModule,
            DxTextBoxModule } from 'devextreme-angular';
  
  @NgModule({
      declarations: [
          AppComponent
      ],
      imports: [
          BrowserModule,
          DxValidatorModule,
          DxTextBoxModule
      ],
      providers: [],
      bootstrap: [AppComponent]
  })
  export class AppModule { }

  Vue

  App.vue

  <template>
      <DxTextBox>
          <DxValidator>
              <DxCompareRule
                  message=""
              />
          </DxValidator>
      </DxTextBox>
  </template>
  
  <script>
  import 'devextreme/dist/css/dx.common.css';
  import 'devextreme/dist/css/dx.light.css';
  
  import { DxTextBox } from 'devextreme-vue/text-box';
  import {
      DxValidator,
      DxCompareRule
  } from 'devextreme-vue/validator';
  
  export default {
      components: {
          DxTextBox,
          DxValidator,
          DxCompareRule
      }
  }
  </script>

  React

  App.js

  import React from 'react';
  
  import 'devextreme/dist/css/dx.common.css';
  import 'devextreme/dist/css/dx.light.css';
  
  import { TextBox } from 'devextreme-react/text-box';
  import {
      Validator,
      CompareRule
  } from 'devextreme-react/validator';
  
  class App extends React.Component {
      render() {
          return (
              <TextBox>
                  <Validator>
                      <CompareRule
                          message="" />
                  </Validator>
              </TextBox>
          );
      }
  }
  export default App;

• Display the editor's name in the message

  jQuery

  index.js

  $(function() {
      $("#textBox").dxTextBox({ ... })
          .dxValidator({
              name: "Passwords", // The error message will be "Passwords do not match"
              validationRules: [{
                  type: "compare"
              }]
          });
  });

  Angular

  app.component.html

  app.module.ts

  <dx-text-box>
      <!-- The error message will be "Passwords do not match" -->
      <dx-validator name="Passwords">
          <dxi-validation-rule 
              type="compare">
          </dxi-validation-rule>
      </dx-validator>
  </dx-text-box>

  import { BrowserModule } from '@angular/platform-browser';
  import { NgModule } from '@angular/core';
  import { AppComponent } from './app.component';
  
  import { DxValidatorModule,
           DxTextBoxModule } from 'devextreme-angular';
  
  @NgModule({
      declarations: [
          AppComponent
      ],
      imports: [
          BrowserModule,
          DxValidatorModule,
          DxTextBoxModule
      ],
      providers: [],
      bootstrap: [AppComponent]
  })
  export class AppModule { }

  Vue

  App.vue

  <template>
      <DxTextBox>
          <!-- The error message will be "Passwords do not match" -->
          <DxValidator name="Passwords">
              <DxCompareRule />
          </DxValidator>
      </DxTextBox>
  </template>
  
  <script>
  import 'devextreme/dist/css/dx.common.css';
  import 'devextreme/dist/css/dx.light.css';
  
  import { DxTextBox } from 'devextreme-vue/text-box';
  import {
      DxValidator,
      DxCompareRule
  } from 'devextreme-vue/validator';
  
  export default {
      components: {
          DxValidator,
          DxCompareRule
      }
  }
  </script>

  React

  App.js

  import React from 'react';
  
  import 'devextreme/dist/css/dx.common.css';
  import 'devextreme/dist/css/dx.light.css';
  
  import { TextBox } from 'devextreme-react/text-box';
  import {
      Validator,
      CompareRule
  } from 'devextreme-react/validator';
  
  class App extends React.Component {
      render() {
          return (
              <TextBox>
                  {/* The error message will be "Passwords do not match" */}
                  <Validator name="Passwords">
                      <CompareRule} />
                  </Validator>
              </TextBox>
          );
      }
  }
  
  export default App;