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DataGridViewCellCancelEventHandler Delegate

Represents the method that will handle the CellBeginEdit and RowValidating events of a DataGridView.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

public delegate void DataGridViewCellCancelEventHandler(
	Object sender,
	DataGridViewCellCancelEventArgs e
)

Parameters

sender
Type: System.Object

The source of the event.

e
Type: System.Windows.Forms.DataGridViewCellCancelEventArgs

A DataGridViewCellCancelEventArgs that contains the event data.

When you create a DataGridViewCellCancelEventHandler 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.

The following code example uses a DataGridViewCellCancelEventHandler delegate to check if valid track and release dates are entered.

    private void ValidateByRow(Object sender, 
        DataGridViewCellCancelEventArgs data) 
    {
        DataGridViewRow row = 
            songsDataGridView.Rows[data.RowIndex];
        DataGridViewCell trackCell = 
            row.Cells[songsDataGridView.Columns["Track"].Index];
        DataGridViewCell dateCell = 
            row.Cells[songsDataGridView.Columns["Release Date"].Index];
        data.Cancel = !(IsTrackGood(trackCell) && IsDateGood(dateCell));
    }

    private Boolean IsTrackGood(DataGridViewCell cell)
    {
        Int32 cellValueAsInt;
        if (cell.Value.ToString().Length == 0)
		{
            cell.ErrorText = "Please enter a track";
            songsDataGridView.Rows[cell.RowIndex].ErrorText = 
                "Please enter a track";
            return false;
        }
        else if (cell.Value.ToString().Equals("0"))
        {
            cell.ErrorText = "Zero is not a valid track";
            songsDataGridView.Rows[cell.RowIndex].ErrorText =
                "Zero is not a valid track";
            return false;
        }
        else if (!Int32.TryParse(cell.Value.ToString(), out cellValueAsInt))
        {
            cell.ErrorText = "A Track must be a number";
            songsDataGridView.Rows[cell.RowIndex].ErrorText =
                "A Track must be a number";
            return false;
        }
        return true;
    }

    private Boolean IsDateGood(DataGridViewCell cell) 
    {
        if (cell.Value == null)
		{
            cell.ErrorText = "Missing date";
            songsDataGridView.Rows[cell.RowIndex].ErrorText = 
                "Missing date";
            return false;
        }
        else
        {
            try
            {
                DateTime.Parse(cell.Value.ToString());
            }
            catch (FormatException)
            {
                cell.ErrorText = "Invalid format";
                songsDataGridView.Rows[cell.RowIndex].ErrorText = 
                    "Invalid format";

                return false;
            }
        }
        return true;
    }

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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