Expression Editor Customization

• Jun 07, 2019

You can customize the Expression Editor. For example, the image below shows the expression editor with the following changes:

• The Columns category is renamed to Fields.
• The Now function is removed from the date-time functions list.

Perform the following steps to customize the expression editor:

1. Handle the DataViewBase.UnboundExpressionEditorCreated (or PivotGridControl.UnboundExpressionEditorCreated) event.

2. Use one of the following properties to obtain the expression editor:

   • ExpressionEditorCreatedEventArgsBase.AutoCompleteExpressionEditorControl (or PivotUnboundExpressionEditorEventArgs.AutoCompleteExpressionEditorControl) – the expression editor in AutoComplete mode, or
   • ExpressionEditorCreatedEventArgsBase.ExpressionEditorControl (or PivotUnboundExpressionEditorEventArgs.ExpressionEditorControl) – the expression editor in Standard mode.
3. Specify the required expression editor’s properties.

The following code sample demonstrates how to customize the AutoComplete expression editor as shown in the image above:

XAML

<dxg:GridControl>
   <!---->            
   <dxg:GridControl.View>
      <dxg:TableView UnboundExpressionEditorCreated="OnUnboundExpressionEditorCreated" />
   </dxg:GridControl.View>
</dxg:GridControl>

C#

void OnUnboundExpressionEditorCreated(object sender, UnboundExpressionEditorEventArgs e) {
   var expressionEditorContext = e.AutoCompleteExpressionEditorControl.Context;   
   var nowFunction = expressionEditorContext.Functions.FirstOrDefault(f => string.Equals(f.Name, "now", StringComparison.OrdinalIgnoreCase));
   if (nowFunction != null) {
      expressionEditorContext.Functions.Remove(nowFunction);
   }   
   foreach (var columnInfo in expressionEditorContext.Columns) {
      columnInfo.Category = "Fields";
   }
}