DataGridView.CellToolTipTextNeeded 事件

定义

需要单元格的工具提示文本时发生。Occurs when a cell's ToolTip text is needed.

public:
 event System::Windows::Forms::DataGridViewCellToolTipTextNeededEventHandler ^ CellToolTipTextNeeded;
public event System.Windows.Forms.DataGridViewCellToolTipTextNeededEventHandler CellToolTipTextNeeded;
member this.CellToolTipTextNeeded : System.Windows.Forms.DataGridViewCellToolTipTextNeededEventHandler 
Public Custom Event CellToolTipTextNeeded As DataGridViewCellToolTipTextNeededEventHandler 

示例

下面的代码示例演示如何使用 @no__t 0 事件处理程序在数据绑定的 @no__t 1 控件中显示隐藏列的信息。The following code example demonstrates how to use a CellToolTipTextNeeded event handler to display information from hidden columns in a data-bound DataGridView control.

void dataGridView1_CellToolTipTextNeeded(object sender,
    DataGridViewCellToolTipTextNeededEventArgs e)
{
    string newLine = Environment.NewLine;
    if (e.RowIndex > -1)
    {
        DataGridViewRow dataGridViewRow1 = dataGridView1.Rows[e.RowIndex];

        // Add the employee's ID to the ToolTipText.
        e.ToolTipText = String.Format("EmployeeID {0}:{1}",
            dataGridViewRow1.Cells["EmployeeID"].Value, newLine);

        // Add the employee's name to the ToolTipText.
        e.ToolTipText += String.Format("{0} {1} {2}{3}",
            dataGridViewRow1.Cells["TitleOfCourtesy"].Value.ToString(),
            dataGridViewRow1.Cells["FirstName"].Value.ToString(),
            dataGridViewRow1.Cells["LastName"].Value.ToString(),
            newLine);

        // Add the employee's title to the ToolTipText.
        e.ToolTipText += String.Format("{0}{1}{2}",
            dataGridViewRow1.Cells["Title"].Value.ToString(),
            newLine, newLine);

        // Add the employee's contact information to the ToolTipText.
        e.ToolTipText += String.Format("{0}{1}{2}, ",
            dataGridViewRow1.Cells["Address"].Value.ToString(), newLine,
            dataGridViewRow1.Cells["City"].Value.ToString());
        if (!String.IsNullOrEmpty(
            dataGridViewRow1.Cells["Region"].Value.ToString()))
        {
            e.ToolTipText += String.Format("{0}, ",
                dataGridViewRow1.Cells["Region"].Value.ToString());
        }
        e.ToolTipText += String.Format("{0}, {1}{2}{3} EXT:{4}{5}{6}",
            dataGridViewRow1.Cells["Country"].Value.ToString(),
            dataGridViewRow1.Cells["PostalCode"].Value.ToString(),
            newLine, dataGridViewRow1.Cells["HomePhone"].Value.ToString(),
            dataGridViewRow1.Cells["Extension"].Value.ToString(),
            newLine, newLine);

        // Add employee information to the ToolTipText.
        DateTime HireDate =
            (DateTime)dataGridViewRow1.Cells["HireDate"].Value;
        e.ToolTipText +=
            String.Format("Employee since: {0}/{1}/{2}{3}Manager: {4}",
            HireDate.Month.ToString(), HireDate.Day.ToString(),
            HireDate.Year.ToString(), newLine,
            dataGridViewRow1.Cells["Manager"].Value.ToString());
    }
}
Public Sub dataGridView1_CellToolTipTextNeeded(ByVal sender As Object, _
    ByVal e As DataGridViewCellToolTipTextNeededEventArgs) _
    Handles dataGridView1.CellToolTipTextNeeded

    Dim newLine As String = Environment.NewLine
    If e.RowIndex > -1 Then
        Dim dataGridViewRow1 As DataGridViewRow = _
        dataGridView1.Rows(e.RowIndex)

        ' Add the employee's ID to the ToolTipText.
        e.ToolTipText = String.Format("EmployeeID {0}: {1}", _
            dataGridViewRow1.Cells("EmployeeID").Value.ToString(), _
            newLine)

        ' Add the employee's name to the ToolTipText.
        e.ToolTipText += String.Format("{0} {1} {2} {3}", _
            dataGridViewRow1.Cells("TitleOfCourtesy").Value.ToString(), _
            dataGridViewRow1.Cells("FirstName").Value.ToString(), _
            dataGridViewRow1.Cells("LastName").Value.ToString(), _
            newLine)

        ' Add the employee's title to the ToolTipText.
        e.ToolTipText += String.Format("{0}{1}{2}", _
            dataGridViewRow1.Cells("Title").Value.ToString(), _
            newLine, newLine)

        ' Add the employee's contact information to the ToolTipText.
        e.ToolTipText += String.Format("{0}{1}{2}, ", _
            dataGridViewRow1.Cells("Address").Value.ToString(), newLine, _
            dataGridViewRow1.Cells("City").Value.ToString())
        If Not String.IsNullOrEmpty( _
            dataGridViewRow1.Cells("Region").Value.ToString())

            e.ToolTipText += String.Format("{0}, ", _
               dataGridViewRow1.Cells("Region").Value.ToString())
        End If
        e.ToolTipText += String.Format("{0}, {1}{2}{3} EXT:{4}{5}{6}", _
            dataGridViewRow1.Cells("Country").Value.ToString(), _
            dataGridViewRow1.Cells("PostalCode").Value.ToString(), _
            newLine, _
            dataGridViewRow1.Cells("HomePhone").Value.ToString(), _
            dataGridViewRow1.Cells("Extension").Value.ToString(), _
            newLine, newLine)

        ' Add employee information to the ToolTipText.
        Dim HireDate As DateTime = _
            CType(dataGridViewRow1.Cells("HireDate").Value, DateTime)
        e.ToolTipText += _
            String.Format("Employee since: {0}/{1}/{2}{3}Manager: {4}", _
                HireDate.Month.ToString(), HireDate.Day.ToString(), _
                HireDate.Year.ToString(), newLine, _
                dataGridViewRow1.Cells("Manager").Value.ToString())
    End If
End Sub

注解

仅当设置了 @no__t 控件 DataSource 属性或其 @no__t 的属性为 true 时,才会发生 @no__t 0 事件。The CellToolTipTextNeeded event occurs only when the DataGridView control DataSource property is set or its VirtualMode property is true.

处理 @no__t 0 事件时,每当鼠标指针位于单元格上时,就会显示您在处理程序中指定的工具提示文本,并且控件 @no__t 属性值 trueWhen you handle the CellToolTipTextNeeded event, the ToolTip text you specify in the handler is shown whenever the mouse pointer is over a cell and the control ShowCellToolTips property value is true. 如果要显示由当前状态或单元值决定的工具提示,则 CellToolTipTextNeeded 事件很有用。The CellToolTipTextNeeded event is useful when you want to display ToolTips determined by the current state or value of a cell.

只要检索 @no__t 属性的值(以编程方式或当鼠标指针进入单元格时),就会发生 CellToolTipTextNeeded 事件。The CellToolTipTextNeeded event also occurs whenever the value of the DataGridViewCell.ToolTipText property is retrieved, either programmatically or when the mouse pointer enters a cell.

您可以使用 DataGridViewCellEventArgs.ColumnIndexRowIndex 属性来确定单元的状态或值,并使用此信息来更改或修改 @no__t 2 属性。You can use the DataGridViewCellEventArgs.ColumnIndex and RowIndex properties to determine the state or value of a cell, and use this information to change or modify the DataGridViewCellToolTipTextNeededEventArgs.ToolTipText property. 此属性将用单元 @no__t 的值(即事件值覆盖的单元格)的值初始化。This property is initialized with the value of the cell ToolTipText property, which the event value overrides.

处理大量数据时处理 @no__t 0 事件,以避免为多个单元格设置单元格 ToolTipText 值时的性能损失。Handle the CellToolTipTextNeeded event when working with large amounts of data to avoid the performance penalties of setting the cell ToolTipText value for multiple cells. 有关详细信息,请参阅 缩放 Windows 窗体 DataGridView 控件的最佳做法For more information, see Best Practices for Scaling the Windows Forms DataGridView Control.

有关如何处理事件的详细信息,请参阅处理和引发事件For more information about how to handle events, see Handling and Raising Events.

适用于

另请参阅