System.Windows.Forms.DataGridViewRowErrorTextNeededEventHandler Delegate

Represents the method that will handle the DataGridView.RowErrorTextNeeded event of a System.Windows.Forms.DataGridView.

Syntax

public delegate void DataGridViewRowErrorTextNeededEventHandler (object sender, DataGridViewRowErrorTextNeededEventArgs e)

Parameters

sender
Documentation for this section has not yet been entered.
e
Documentation for this section has not yet been entered.

Remarks

The DataGridView.RowErrorTextNeeded event occurs only when the System.Windows.Forms.DataGridView control DataGridView.DataSource property is set or its DataGridView.VirtualMode property is true. Handling the DataGridView.RowErrorTextNeeded event is useful when you want to determine the error for a row depending on its state and the values it contains.

When you handle the DataGridView.RowErrorTextNeeded event and specify error text in the handler, an error glyph appears in the row header unless the DataGridView.ShowRowErrors property is set to false. When the user moves the mouse pointer over the error glyph, the error text appears in a ToolTip.

The DataGridView.RowErrorTextNeeded event also occurs whenever the value of the DataGridViewRow.ErrorText property is retrieved.

You can use the DataGridViewRowErrorTextNeededEventArgs.RowIndex property to determine the state or value of a row, and use this information to change or modify the DataGridViewRowErrorTextNeededEventArgs.ErrorText property. This property is initialized with the value of the row DataGridViewRow.ErrorText property, which the event value overrides.

Handle the DataGridView.RowErrorTextNeeded event when working with large amounts of data to avoid the performance penalties of setting the row DataGridViewRow.ErrorText value for multiple rows. For more information, see Best Practices for Scaling the Windows Forms DataGridView Control.

For more information about handling events, see Consuming Events.

When you create a System.Windows.Forms.DataGridViewRowErrorTextNeededEventHandler delegate, you identify the method that will handle the event. To associate the event with your event handler, add an instance of the delegate to the event. The event handler is called whenever the event occurs, unless you remove the delegate. For more information about event-handler delegates, see Events and Delegates.

Requirements

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
Assembly Versions: 2.0.0.0
Since: .NET 2.0