操作說明：自訂 Windows Forms DataGridView 控制項中的資料格式

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下列程式碼範例示範如何實作 DataGridView.CellFormatting 事件的處理常式，這會根據其資料行和值變更儲存格的顯示方式。

包含負數之資料行中的 Balance 儲存格已指定為紅色背景。 您也可以格式化這些儲存格為貨幣，在負值周圍顯示括號。 如需詳細資訊，請參閱如何：格式化 Windows Forms DataGridView 控制項中的資料。

Priority 資料行中的儲存格會顯示影像取代對應的文字儲存格的值。 DataGridViewCellFormattingEventArgs 的 Value 屬性用來取得文字儲存格的值，並設定對應的影像顯示值。

範例

using System;
using System.Drawing;
using System.Windows.Forms;

public class Form1 : Form
{
    private DataGridView dataGridView1 = new DataGridView();
    private Bitmap highPriImage;
    private Bitmap mediumPriImage;
    private Bitmap lowPriImage;

    public Form1()
    {
        // Initialize the images.
        try
        {
            highPriImage = new Bitmap("highPri.bmp");
            mediumPriImage = new Bitmap("mediumPri.bmp");
            lowPriImage = new Bitmap("lowPri.bmp");
        }
        catch (ArgumentException)
        {
            MessageBox.Show("The Priority column requires Bitmap images " +
                "named highPri.bmp, mediumPri.bmp, and lowPri.bmp " +
                "residing in the same directory as the executable file.");
        }

        // Initialize the DataGridView.
        dataGridView1.Dock = DockStyle.Fill;
        dataGridView1.AllowUserToAddRows = false;
        dataGridView1.Columns.AddRange(
            new DataGridViewTextBoxColumn(),
            new DataGridViewImageColumn());
        dataGridView1.Columns[0].Name = "Balance";
        dataGridView1.Columns[1].Name = "Priority";
        dataGridView1.Rows.Add("-100", "high");
        dataGridView1.Rows.Add("0", "medium");
        dataGridView1.Rows.Add("100", "low");
        dataGridView1.CellFormatting +=
            new System.Windows.Forms.DataGridViewCellFormattingEventHandler(
            this.dataGridView1_CellFormatting);
        this.Controls.Add(dataGridView1);
    }

    // Changes how cells are displayed depending on their columns and values.
    private void dataGridView1_CellFormatting(object sender,
        System.Windows.Forms.DataGridViewCellFormattingEventArgs e)
    {
        // Set the background to red for negative values in the Balance column.
        if (dataGridView1.Columns[e.ColumnIndex].Name.Equals("Balance"))
        {
            Int32 intValue;
            if (Int32.TryParse((String)e.Value, out intValue) &&
                (intValue < 0))
            {
                e.CellStyle.BackColor = Color.Red;
                e.CellStyle.SelectionBackColor = Color.DarkRed;
            }
        }

        // Replace string values in the Priority column with images.
        if (dataGridView1.Columns[e.ColumnIndex].Name.Equals("Priority"))
        {
            // Ensure that the value is a string.
            String stringValue = e.Value as string;
            if (stringValue == null) return;

            // Set the cell ToolTip to the text value.
            DataGridViewCell cell = dataGridView1[e.ColumnIndex, e.RowIndex];
            cell.ToolTipText = stringValue;

            // Replace the string value with the image value.
            switch (stringValue)
            {
                case "high":
                    e.Value = highPriImage;
                    break;
                case "medium":
                    e.Value = mediumPriImage;
                    break;
                case "low":
                    e.Value = lowPriImage;
                    break;
            }
        }
    }

    public static void Main()
    {
        Application.Run(new Form1());
    }
}

Imports System.Drawing
Imports System.Windows.Forms

Public Class Form1
    Inherits Form

    Private WithEvents dataGridView1 As New DataGridView()
    Private highPriImage As Bitmap
    Private mediumPriImage As Bitmap
    Private lowPriImage As Bitmap

    Public Sub New()

        ' Initialize the images. 
        Try
            highPriImage = New Bitmap("highPri.bmp")
            mediumPriImage = New Bitmap("mediumPri.bmp")
            lowPriImage = New Bitmap("lowPri.bmp")
        Catch ex As ArgumentException
            MessageBox.Show("The Priority column requires Bitmap images" & _
                "named highPri.bmp, mediumPri.bmp, and lowPri.bmp " & _
                "residing in the same directory as the executable file.")
        End Try

        ' Initialize the DataGridView.
        With dataGridView1
            .Dock = DockStyle.Fill
            .AllowUserToAddRows = False
            .Columns.AddRange( _
                New DataGridViewTextBoxColumn(), _
                New DataGridViewImageColumn())
            .Columns(0).Name = "Balance"
            .Columns(1).Name = "Priority"
            .Rows.Add("-100", "high")
            .Rows.Add("0", "medium")
            .Rows.Add("100", "low")
        End With

        Me.Controls.Add(dataGridView1)

    End Sub

    ' Changes how cells are displayed depending on their columns and values.
    Private Sub dataGridView1_CellFormatting(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) _
        Handles dataGridView1.CellFormatting

        ' Set the background to red for negative values in the Balance column.
        If dataGridView1.Columns(e.ColumnIndex).Name.Equals("Balance") Then

            'Dim intValue As Int32
            If CInt(e.Value) < 0 Then
                'if Int32.TryParse((String)e.Value, out intValue) && 
                '   (intValue < 0))

                e.CellStyle.BackColor = Color.Red
                e.CellStyle.SelectionBackColor = Color.DarkRed
            End If
        End If

        ' Replace string values in the Priority column with images.
        If dataGridView1.Columns(e.ColumnIndex).Name.Equals("Priority") Then

            ' Ensure that the value is a string.
            Dim stringValue As String = TryCast(e.Value, String)
            If stringValue Is Nothing Then Return

            ' Set the cell ToolTip to the text value.
            Dim cell As DataGridViewCell = _
                dataGridView1(e.ColumnIndex, e.RowIndex)
            cell.ToolTipText = stringValue

            ' Replace the string value with the image value.
            Select Case stringValue

                Case "high"
                    e.Value = highPriImage
                Case "medium"
                    e.Value = mediumPriImage
                Case "low"
                    e.Value = lowPriImage

            End Select

        End If

    End Sub

    Public Sub Main()
        Application.Run(New Form1())
    End Sub

End Class

編譯程式碼

這個範例需要：

  • System、System.Drawing 和 System.Windows.Forms 組件的參考。

  • 名為 highPri.bmp、mediumPri.bmp 和 lowPri.bmp 的 Bitmap 影像位於與可執行檔相同的目錄中。

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