Events

The DataForm exposes a set of events that are raised on different occasions.

• AutoGeneratingField—Fires during the automatic creation of a data field. The event is raised for each data field that will be created and can be used to modify or replace the field. The event arguments are of type AutoGeneratingFieldEventArgs and provide access to information for the edited property, the display index of the data field, and the data field itself.

  AutoGeneratingField Event Handler

      private void RadDataForm_AutoGeneratingField(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.AutoGeneratingFieldEventArgs e) 
      { 
          DataFormDataField datafield = e.DataField; 
          int? displayIndex = e.Order; 
          string propertyName = e.PropertyName; 
          Type propertyType = e.PropertyType; 
   
          if (propertyName == "PropertyThatShouldNotBePresentedInTheUI") 
          { 
              e.Cancel = true; 
          } 
      } 
  

• DataFieldPreparedEditor—Fires when the editor of the associated data field is created. The event arguments are of type DataFieldPreparedEditorEventArgs, which provide information about the editor and the data field object.

  DataFieldPreparedEditor Event Handler

      private void RadDataForm_DataFieldPreparedEditor(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.DataFieldPreparedEditorEventArgs e) 
      { 
          DataFormDataField datafield = e.DataField; 
          FrameworkElement editor = e.Editor; 
      } 
  

• CurrentItemChanged—Fires when the currently selected item changes.

• InitializingNewItem—Fires when the creation of a new item begins. The event arguments are of type InitializingNewItemEventArgs, which allows you to replace or edit the created item, or cancel the creation.

  InitializingNewItem Event Handler

      private void RadDataForm_InitializingNewItem(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.InitializingNewItemEventArgs e) 
      { 
          e.DataItem = new MyDataItem(); 
      } 
  

• AddingNewItem—Fires when a new item is added through the UI or the API of the component. The event arguments are of type AddingNewItemEventArgs, which can be used to cancel the adding of the item.

  AddingNewItem Event Handler

      private void RadDataForm_AddingNewItem(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.AddingNewItemEventArgs e) 
      { 
          if (shouldNotAllowNewItemAdding) 
          { 
              e.Cancel = true; 
          } 
      } 
  

• AddedNewItem—Fires after a new item is added in the ItemsSource through the UI or the API of the component. The event arguments are of type AddedNewItemEventArgs and contain information about the newly added item.

  AddedNewItem Event Handler

      private void RadDataForm_AddedNewItem(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.AddedNewItemEventArgs e) 
      { 
          object addedItem = e.NewItem; 
      } 
  

• DeletingItem—Fires when an item is deleted through the UI or the API of the component. The event arguments are of type CancelEventArgs, which can be used to cancel the deletion of the item.

  DeletingItem Event Handler

      private void RadDataForm_DeletingItem(object sender, CancelEventArgs e) 
      { 
          if (shouldNotAllowItemDeleting) 
          { 
              e.Cancel = true; 
          } 
      } 
  

• DeletedItem—Fires after an item was deleted through the UI or the API of the component. The event arguments are of type ItemDeletedEventArgs, which provides access to the deleted item.

  DeletedItem Event Handler

      private void RadDataForm_DeletedItem(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.ItemDeletedEventArgs e) 
      { 
          object removedItem = e.DeletedItem; 
      } 
  

• BeginningEdit—Fires when editing is beginning. The event arguments are of type CancelEventArgs, which can be used to cancel the beginning of the item edit.

  BeginningEdit Event Handler

      private void RadDataForm_BeginningEdit(object sender, CancelEventArgs e) 
      { 
          if (shouldNotAllowEditStart) 
          { 
              e.Cancel = true; 
          } 
      } 
  

• EditEnding—Fires when editing is ending. The event arguments are of type EditEndingEventArgs, which can be used to cancel the ending of the item edit and also to get the edit action (cancel or commit).

  EditEnding Event Handler

      private void RadDataForm_EditEnding(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.EditEndingEventArgs e) 
      { 
          EditAction action = e.EditAction; 
          if (shouldCancelEditEnded) 
          { 
              e.Cancel = true; 
          } 
      } 
  

• EditEnded—Fires after editing ends. The event arguments are of type EditEndedEventArgs, which allows you to get the edit action (cancel or commit).

  EditEnded Event Handler

      private void RadDataForm_EditEnded(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.EditEndedEventArgs e) 
      { 
          EditAction action = e.EditAction; 
      } 
  

• DataFieldBeginningEdit—Fires when the editing of the data field is beginning. The event arguments are of type DataFieldCancelEventArgs, which allows you to cancel the editing and also to get the associated data field object.

  DataFieldBeginningEdit Event Handler

      private void RadDataForm_DataFieldBeginningEdit(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.DataFieldCancelEventArgs e) 
      { 
          DataFormDataField datafield = e.DataField; 
          if (shouldCancelEditStart) 
          { 
              e.Cancel = true; 
          } 
      } 
  

• DataFieldEditEnded—Fires after editing ends. The event arguments are of type DataFieldEditEndedEventArgs, which allows you to get the edit action (cancel or commit) and also the previous and new values.

  DataFieldEditEnded Event Handler

      private void dataForm_DataFieldEditEnded(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.DataFieldEditEndedEventArgs e) 
      { 
          DataFormDataField datafield = e.DataField; 
          EditAction action = e.EditAction; 
          object newValue = e.NewValue; 
          object previousValue = e.OldValue; 
      } 
  

• ValidatingItem—Fires when an item is being validated. The event arguments are of type CancelEventArgs, which can be used to cancel the validation of the item.

  ValidatingItem Event Handler

      private void RadDataForm_ValidatingItem(object sender, CancelEventArgs e) 
      { 
          if (shouldCancelItemValidating) 
          { 
              e.Cancel = true; 
          } 
      } 
  

• DataFieldValidating—Fires when a data field value is being validated. The event arguments are of type DataFieldValidatingEventArgs, which provide information about the validation state of the field and also about the new and old value in the editor.

  DataFieldValidating Event Handler

      private void RadDataForm_DataFieldValidating(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.DataFieldValidatingEventArgs e) 
      { 
          DataFormDataField datafield = e.DataField; 
          object newValue = e.NewValue; 
          object previousValue = e.OldValue; 
          IEnumerable<ValidationResult> results = e.ValidationResults; 
   
          if (!isTheDataFieldValid) 
          { 
              e.IsValid = false; 
          }             
      } 
  

• DataFieldValidated—Fires after the data field validation ends. The event arguments are of type DataFieldValidatedEventArgs, which provide information about the validation results and also about the data field object.

  DataFieldValidated Event Handler

      private void RadDataForm_DataFieldValidated(object sender, Telerik.UI.Xaml.Controls.Data.DataForm.DataFieldValidatedEventArgs e) 
      { 
         DataFormDataField datafield = e.DataField; 
         IEnumerable<ValidationResult> results = e.ValidationResults; 
      } 
  

  See Also

• Getting Started with the Telerik UI for WinUI DataForm
• Visual Structure