Two-Way Data Binding

• Oct 29, 2020
• 2 minutes to read

DevExpress Blazor components support two-way data binding (refer to ASP.NET Core Blazor data binding). This means you can use the @bind attribute to implement binding between a component’s property and a data field.

The following code uses the @bind-Text attribute to bind a text editor’s Text property to a TextValue data field. When the editor is rendered, the property’s value comes from the bound field. When a user changes the input value and removes focus, the property’s value is updated.

<DxTextBox @bind-Text="@TextValue"></DxTextBox>

@code {
    string TextValue { get; set; } = "Some text";
}

This code is equivalent to the following code:

<DxTextBox Text="@TextValue"
           TextExpression="@(() => TextValue)"
           TextChanged="@((newValue) => OnTextChanged(newValue))">
</DxTextBox>

@code {
    string TextValue { get; set; } = "Some text";

    void OnTextChanged(string newValue) {
        Text = newValue;
    }
}

When you use the @bind attribute, the Text, TextExpression properties and the TextChanged event are set internally. If you do not use two-way binding, set these properties and event explicitly. Note that the TextExpression property is used only if the editor is placed in the EditForm.

Examples

You can use two-way data binding for DevExpress Blazor components that have a <PropertyName> property and a <PropertyName>Changed event, for example:

• DxDateEdit. Use @bind-Date, or set Date, DateExpression, and DateChanged.

  <DxDateEdit @bind-Date="@DateTimeValue"></DxDateEdit>
  @* or set Date, DateExpression, and DateChanged *@
  
  @code {
      DateTime DateTimeValue { get; set; } = DateTime.Today;
  }
  

• DxComboBox. Use @bind-Value, or set Value, ValueExpression, and ValueChanged.

  <DxComboBox Data="@Cities" @bind-Value="@Value"></DxComboBox>
  @* or set Value, ValueExpression, and ValueChanged *@
  
  @code {
      IEnumerable<string> Cities = new List<string>() {
          "London",
          "Berlin",
          "Paris",
      };
  
      string Value { get; set; }
  }
  

• DxCheckBox. Use @bind-Checked, or set Checked, CheckedExpression, and CheckedChanged.

  <DxCheckBox @bind-Checked="@Value"></DxCheckBox>
  @* or set Checked, CheckedExpression, and CheckedChanged *@
  
  @code {
      bool Value { get; set; }
  }