DataGridViewRowEventHandler Delegate

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Source:

DataGridViewEventHandlers.cs

Represents the method that will handle row-related events of a DataGridView.

public delegate void DataGridViewRowEventHandler(System::Object ^ sender, DataGridViewRowEventArgs ^ e);

public delegate void DataGridViewRowEventHandler(object? sender, DataGridViewRowEventArgs e);

type DataGridViewRowEventHandler = delegate of obj * DataGridViewRowEventArgs -> unit

Public Delegate Sub DataGridViewRowEventHandler(sender As Object, e As DataGridViewRowEventArgs)

Parameters

sender

Object

The source of the event.

e

DataGridViewRowEventArgs

A DataGridViewRowEventArgs that contains the event data.

Examples

The following code example uses a DataGridViewRowEventHandler delegate to handle the NewRowNeeded event. This code example is part of a larger example provided in the VirtualMode property reference topic.

    void VirtualConnector::dataGridView1_NewRowNeeded
        (Object^ sender, DataGridViewRowEventArgs^ e)
    {
        newRowNeeded = true;
    }

    void VirtualConnector::dataGridView1_RowsAdded
        (Object^ sender, DataGridViewRowsAddedEventArgs^ e)
    {
        if (newRowNeeded)
        {
            newRowNeeded = false;
            numberOfRows = numberOfRows + 1;
        }
    }

#pragma region Data store maintance

    void VirtualConnector::dataGridView1_CellValueNeeded
        (Object^ sender, DataGridViewCellValueEventArgs^ e)
    {
        if (store->ContainsKey(e->RowIndex))
        {
            // Use the store if the e value has been modified 
            // and stored.            
            e->Value = gcnew Int32(store->default[e->RowIndex]); 
        }
        else if (newRowNeeded && e->RowIndex == numberOfRows)
        {
            if (dataGridView1->IsCurrentCellInEditMode)
            {
                e->Value = initialValue;
            }
            else
            {
                // Show a blank e if the cursor is just loitering
                // over(the) last row.
                e->Value = String::Empty;
            }
        }
        else
        {
            e->Value = e->RowIndex;
        }
    }

    void VirtualConnector::dataGridView1_CellValuePushed
        (Object^ sender, DataGridViewCellValueEventArgs^ e)
    {
        String^ value = e->Value->ToString();
        store[e->RowIndex] = Int32::Parse(value, 
            CultureInfo::CurrentCulture);
    }
#pragma endregion

bool newRowNeeded;
private void dataGridView1_NewRowNeeded(object sender,
    DataGridViewRowEventArgs e)
{
    newRowNeeded = true;
}

const int initialSize = 5000000;
int numberOfRows = initialSize;

private void dataGridView1_RowsAdded(object sender,
     DataGridViewRowsAddedEventArgs e)
{
    if (newRowNeeded)
    {
        newRowNeeded = false;
        numberOfRows = numberOfRows + 1;
    }
}

#region "data store maintance"
const int initialValue = -1;

private void dataGridView1_CellValueNeeded(object sender,
    DataGridViewCellValueEventArgs e)
{
    if (store.ContainsKey(e.RowIndex))
    {
        // Use the store if the e value has been modified 
        // and stored.            
        e.Value = store[e.RowIndex];
    }
    else if (newRowNeeded && e.RowIndex == numberOfRows)
    {
        if (dataGridView1.IsCurrentCellInEditMode)
        {
            e.Value = initialValue;
        }
        else
        {
            // Show a blank value if the cursor is just resting
            // on the last row.
            e.Value = String.Empty;
        }
    }
    else
    {
        e.Value = e.RowIndex;
    }
}

private void dataGridView1_CellValuePushed(object sender,
    DataGridViewCellValueEventArgs e)
{
    store.Add(e.RowIndex, int.Parse(e.Value.ToString()));
}
#endregion

private Dictionary<int, int> store = new Dictionary<int, int>();

    Dim newRowNeeded As Boolean

    Private Sub dataGridView1_NewRowNeeded(ByVal sender As Object, _
        ByVal e As DataGridViewRowEventArgs) _
        Handles dataGridView1.NewRowNeeded

        newRowNeeded = True
    End Sub

    Const initialSize As Integer = 5000000
    Dim numberOfRows As Integer = initialSize

    Private Sub dataGridView1_RowsAdded(ByVal sender As Object, _
        ByVal e As DataGridViewRowsAddedEventArgs) _
        Handles dataGridView1.RowsAdded

        If newRowNeeded Then
            newRowNeeded = False
            numberOfRows = numberOfRows + 1
        End If
    End Sub

#Region "data store maintance"
    Const initialValue As Integer = -1

    Private Sub dataGridView1_CellValueNeeded(ByVal sender As Object, _
        ByVal e As DataGridViewCellValueEventArgs) _
        Handles dataGridView1.CellValueNeeded

        If store.ContainsKey(e.RowIndex) Then
            ' Use the store if the e value has been modified 
            ' and stored.
            e.Value = store(e.RowIndex)
        ElseIf newRowNeeded AndAlso e.RowIndex = numberOfRows Then
            If dataGridView1.IsCurrentCellInEditMode Then
                e.Value = initialValue
            Else
                ' Show a blank value if the cursor is just resting
                ' on the last row.
                e.Value = String.Empty
            End If
        Else
            e.Value = e.RowIndex
        End If
    End Sub

    Private Sub dataGridView1_CellValuePushed(ByVal sender As Object, _
        ByVal e As DataGridViewCellValueEventArgs) _
        Handles dataGridView1.CellValuePushed

        store.Add(e.RowIndex, CInt(e.Value))

    End Sub
#End Region

    Dim store As System.Collections.Generic.Dictionary(Of Integer, Integer) = _
        New Dictionary(Of Integer, Integer)

Remarks

The DataGridViewRowEventHandler handles the following DataGridView events:

• DefaultValuesNeeded

• NewRowNeeded

• RowDefaultCellStyleChanged

• RowErrorTextChanged

• RowHeaderCellChanged

• RowHeightChanged

• RowMinimumHeightChanged

• RowUnshared

• UserAddedRow

• UserDeletedRow

• RowContextMenuStripChanged

• RowDividerHeightChanged

When you create a DataGridViewRowEventHandler 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 Handling and Raising Events.

Extension Methods

See also

• DataGridView
• DataGridViewRowEventArgs