DataGridViewCellErrorTextNeededEventHandler DataGridViewCellErrorTextNeededEventHandler DataGridViewCellErrorTextNeededEventHandler DataGridViewCellErrorTextNeededEventHandler Delegate

定義

CellErrorTextNeededDataGridView イベントを処理するメソッドを表します。Represents the method that will handle the CellErrorTextNeeded event of a DataGridView.

public delegate void DataGridViewCellErrorTextNeededEventHandler(System::Object ^ sender, DataGridViewCellErrorTextNeededEventArgs ^ e);
public delegate void DataGridViewCellErrorTextNeededEventHandler(object sender, DataGridViewCellErrorTextNeededEventArgs e);
type DataGridViewCellErrorTextNeededEventHandler = delegate of obj * DataGridViewCellErrorTextNeededEventArgs -> unit
Public Delegate Sub DataGridViewCellErrorTextNeededEventHandler(sender As Object, e As DataGridViewCellErrorTextNeededEventArgs)

パラメーター

sender
Object Object Object Object

イベントのソース。The source of the event.

継承
DataGridViewCellErrorTextNeededEventHandlerDataGridViewCellErrorTextNeededEventHandlerDataGridViewCellErrorTextNeededEventHandlerDataGridViewCellErrorTextNeededEventHandler

次のコード例に示します、DataGridViewCellErrorTextNeededEventHandler必要のあるセルのエラー テキストを設定するデリゲート。The following code example demonstrates a DataGridViewCellErrorTextNeededEventHandler delegate that sets the error text for the cell that needs it.

ToolStripMenuItem^ wholeTable;
ToolStripMenuItem^ lookUp;
System::Windows::Forms::ContextMenuStrip^ strip;
String^ cellErrorText;

void dataGridView1_CellContextMenuStripNeeded( Object^ /*sender*/,
    DataGridViewCellContextMenuStripNeededEventArgs^ e )
{
    cellErrorText = String::Empty;
    if ( strip == nullptr )
    {
        strip = gcnew System::Windows::Forms::ContextMenuStrip;
        lookUp->Text = L"Look Up";
        wholeTable->Text = L"See Whole Table";
        strip->Items->Add( lookUp );
        strip->Items->Add( wholeTable );
    }

    e->ContextMenuStrip = strip;
}

void wholeTable_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
{
    dataGridView1->DataSource = Populate( L"Select * from employees", true );
}

DataGridViewCellEventArgs^ theCellImHoveringOver;
void dataGridView1_CellMouseEnter( Object^ /*sender*/, DataGridViewCellEventArgs^ e )
{
    theCellImHoveringOver = e;
}

DataGridViewCellEventArgs^ cellErrorLocation;
void lookUp_Click( Object^ /*sender*/, EventArgs^ /*e*/ )
{
    try
    {
        dataGridView1->DataSource = Populate( String::Format( L"Select * from employees where {0} = '{1}'", dataGridView1->Columns[ theCellImHoveringOver->ColumnIndex ]->Name, dataGridView1->Rows[ theCellImHoveringOver->RowIndex ]->Cells[ theCellImHoveringOver->ColumnIndex ]->Value ), true );
    }
    catch ( ... ) 
    {
        cellErrorText = L"Can't look this cell up";
        cellErrorLocation = theCellImHoveringOver;
    }

}

void dataGridView1_CellErrorTextNeeded( Object^ /*sender*/, DataGridViewCellErrorTextNeededEventArgs^ e )
{
    if ( cellErrorLocation != nullptr )
    {
        if ( e->ColumnIndex == cellErrorLocation->ColumnIndex && e->RowIndex == cellErrorLocation->RowIndex )
        {
            e->ErrorText = cellErrorText;
        }
    }
}

DataTable^ Populate( String^ query, bool resetUnsharedCounter )
{
    if ( resetUnsharedCounter )
    {
        ResetCounter();
    }


    // Alter the data source as necessary
    SqlDataAdapter^ adapter = gcnew SqlDataAdapter( query,
        gcnew SqlConnection( L"Integrated Security=SSPI;Persist Security Info=False;"
        L"Initial Catalog=Northwind;Data Source= localhost" ) );
    DataTable^ table = gcnew DataTable;
    adapter->Fill( table );
    return table;
}

Label^ count;
int unsharedRowCounter;
void ResetCounter()
{
    unsharedRowCounter = 0;
    count->Text = unsharedRowCounter.ToString();
}
private ToolStripMenuItem wholeTable = new ToolStripMenuItem();
private ToolStripMenuItem lookUp = new ToolStripMenuItem();
private ContextMenuStrip strip;
private string cellErrorText;

private void dataGridView1_CellContextMenuStripNeeded(object sender,
    DataGridViewCellContextMenuStripNeededEventArgs e)
{
    cellErrorText = String.Empty;

    if (strip == null)
    {
        strip = new ContextMenuStrip();
        lookUp.Text = "Look Up";
        wholeTable.Text = "See Whole Table";
        strip.Items.Add(lookUp);
        strip.Items.Add(wholeTable);
    }
    e.ContextMenuStrip = strip;
}

private void wholeTable_Click(object sender, EventArgs e)
{
    dataGridView1.DataSource = Populate("Select * from employees", true);
}

private DataGridViewCellEventArgs theCellImHoveringOver;

private void dataGridView1_CellMouseEnter(object sender, DataGridViewCellEventArgs e)
{
    theCellImHoveringOver = e;
}

private DataGridViewCellEventArgs cellErrorLocation;

private void lookUp_Click(object sender, EventArgs e)
{
    try
    {
        dataGridView1.DataSource = Populate("Select * from employees where " +
            dataGridView1.Columns[theCellImHoveringOver.ColumnIndex].Name + " = '" +
            dataGridView1.Rows[theCellImHoveringOver.RowIndex].
            Cells[theCellImHoveringOver.ColumnIndex].Value + "'",
            true);
    }
    catch (SqlException)
    {
        cellErrorText = "Can't look this cell up";
        cellErrorLocation = theCellImHoveringOver;
    }
}

private void dataGridView1_CellErrorTextNeeded(object sender,
    DataGridViewCellErrorTextNeededEventArgs e)
{
    if (cellErrorLocation != null)
    {
        if (e.ColumnIndex == cellErrorLocation.ColumnIndex &&
            e.RowIndex == cellErrorLocation.RowIndex)
        {
            e.ErrorText = cellErrorText;
        }
    }
}

private DataTable Populate(string query, bool resetUnsharedCounter)
{
    if (resetUnsharedCounter)
    {
        ResetCounter();
    }

    // Alter the data source as necessary
    SqlDataAdapter adapter = new SqlDataAdapter(query,
        new SqlConnection("Integrated Security=SSPI;Persist Security Info=False;" +
        "Initial Catalog=Northwind;Data Source=localhost"));

    DataTable table = new DataTable();
    table.Locale = System.Globalization.CultureInfo.InvariantCulture;
    adapter.Fill(table);
    return table;
}

private Label count = new Label();
private int unsharedRowCounter;

private void ResetCounter()
{
    unsharedRowCounter = 0;
    count.Text = unsharedRowCounter.ToString();
}
Private WithEvents wholeTable As New ToolStripMenuItem()
Private WithEvents lookUp As New ToolStripMenuItem()
Private strip As ContextMenuStrip
Private cellErrorText As String

Private Sub dataGridView1_CellContextMenuStripNeeded(ByVal sender As Object, _
    ByVal e As DataGridViewCellContextMenuStripNeededEventArgs) _
    Handles dataGridView1.CellContextMenuStripNeeded

    cellErrorText = String.Empty

    If strip Is Nothing Then
        strip = New ContextMenuStrip()
        lookUp.Text = "Look Up"
        wholeTable.Text = "See Whole Table"
        strip.Items.Add(lookUp)
        strip.Items.Add(wholeTable)
    End If
    e.ContextMenuStrip = strip
End Sub

Private Sub wholeTable_Click(ByVal sender As Object, ByVal e As EventArgs) Handles wholeTable.Click
    dataGridView1.DataSource = Populate("Select * from employees", True)
End Sub

Private theCellImHoveringOver As DataGridViewCellEventArgs

Private Sub dataGridView1_CellMouseEnter(ByVal sender As Object, _
    ByVal e As DataGridViewCellEventArgs) _
    Handles dataGridView1.CellMouseEnter

    theCellImHoveringOver = e
End Sub

Private cellErrorLocation As DataGridViewCellEventArgs

Private Sub lookUp_Click(ByVal sender As Object, ByVal e As EventArgs) Handles lookUp.Click
    Try
        dataGridView1.DataSource = Populate("Select * from employees where " & _
            dataGridView1.Columns(theCellImHoveringOver.ColumnIndex).Name & " = '" & _
            dataGridView1.Rows(theCellImHoveringOver.RowIndex).Cells(theCellImHoveringOver.ColumnIndex).Value.ToString() & _
            "'", True)
    Catch ex As SqlException
        cellErrorText = "Can't look this cell up"
        cellErrorLocation = theCellImHoveringOver
    End Try
End Sub

Private Sub dataGridView1_CellErrorTextNeeded(ByVal sender As Object, _
            ByVal e As DataGridViewCellErrorTextNeededEventArgs) _
            Handles dataGridView1.CellErrorTextNeeded
    If (Not cellErrorLocation Is Nothing) Then
        If e.ColumnIndex = cellErrorLocation.ColumnIndex AndAlso _
            e.RowIndex = cellErrorLocation.RowIndex Then
            e.ErrorText = cellErrorText
        End If
    End If
End Sub

Private Function Populate(ByVal query As String, ByVal resetUnsharedCounter As Boolean) As DataTable

    If resetUnsharedCounter Then
        ResetCounter()
    End If

    ' Alter the data source as necessary
    Dim adapter As New SqlDataAdapter(query, _
        New SqlConnection("Integrated Security=SSPI;Persist Security Info=False;" & _
        "Initial Catalog=Northwind;Data Source=localhost"))

    Dim table As New DataTable()
    table.Locale = System.Globalization.CultureInfo.InvariantCulture
    adapter.Fill(table)
    Return table
End Function

Private count As New Label()
Private unsharedRowCounter As Integer

Private Sub ResetCounter()
    unsharedRowCounter = 0
    count.Text = unsharedRowCounter.ToString()
End Sub

注釈

CellErrorTextNeededのみイベントが発生したときに、DataGridViewコントロールDataSourceプロパティを設定またはそのVirtualModeプロパティはtrueThe CellErrorTextNeeded event occurs only when the DataGridView control DataSource property is set or its VirtualMode property is true. 処理、CellErrorTextNeededイベントは、その値または状態に応じてセルのエラーを確認する場合に便利です。Handling the CellErrorTextNeeded event is useful when you want to determine the error for a cell depending on its value or state.

処理するとき、CellErrorTextNeededイベント指定エラー テキスト ハンドラーでエラー グリフがセルに表示しない限り、および、DataGridView.ShowCellErrorsプロパティに設定されてfalseまたはセルが編集モードにします。When you handle the CellErrorTextNeeded event and specify error text in the handler, an error glyph appears in the cell unless the DataGridView.ShowCellErrors property is set to false or the cell is in edit mode. エラー グリフ上、マウス ポインターを移動すると、エラー テキストがツールヒントに表示されます。When the user moves the mouse pointer over the error glyph, the error text appears in a ToolTip.

CellErrorTextNeededたびにイベントにも発生の値、DataGridViewCell.ErrorTextプロパティを取得します。The CellErrorTextNeeded event also occurs whenever the value of the DataGridViewCell.ErrorText property is retrieved.

使用することができます、DataGridViewCellEventArgs.RowIndexColumnIndex状態または、セルの値を特定し、この情報を使用して、変更または変更するプロパティ、DataGridViewCellErrorTextNeededEventArgs.ErrorTextプロパティ。You can use the DataGridViewCellEventArgs.RowIndex and ColumnIndex property to determine the state or value of a cell, and use this information to change or modify the DataGridViewCellErrorTextNeededEventArgs.ErrorText property. このプロパティは、セルの値で初期化されますErrorTextプロパティで、イベント値より優先されます。This property is initialized with the value of the cell ErrorText property, which the event value overrides.

処理、CellErrorTextNeeded大量のデータ セルを設定したパフォーマンスの低下を回避するために使用する場合、イベントErrorText複数のセルの値。Handle the CellErrorTextNeeded event when working with large amounts of data to avoid the performance penalties of setting the cell ErrorText value for multiple cells. 詳細については、次を参照してください。 Windows フォーム DataGridView コントロールを拡張するためのベスト プラクティスします。For more information, see Best Practices for Scaling the Windows Forms DataGridView Control.

イベントを処理する方法の詳細については、次を参照してください。処理とイベントの発生します。For more information about how to handle events, see Handling and Raising Events.

DataGridViewCellErrorTextNeededEventHandler デリゲートを作成する場合は、イベントを処理するメソッドを指定します。When you create a DataGridViewCellErrorTextNeededEventHandler delegate, you identify the method that will handle the event. イベントをイベント ハンドラーに関連付けるには、デリゲートのインスタンスをイベントに追加します。To associate the event with your event handler, add an instance of the delegate to the event. デリゲートを削除しない限り、そのイベントが発生すると常にイベント ハンドラーが呼び出されます。The event handler is called whenever the event occurs, unless you remove the delegate. イベント ハンドラー デリゲートの詳細については、次を参照してください。処理とイベントの発生します。For more information about event-handler delegates, see Handling and Raising Events.

Extension Methods

GetMethodInfo(Delegate) GetMethodInfo(Delegate) GetMethodInfo(Delegate) GetMethodInfo(Delegate)

指定したデリゲートによって表されるメソッドを表すオブジェクトを取得します。Gets an object that represents the method represented by the specified delegate.

適用対象

こちらもご覧ください