如何:在 Windows 窗体 DataGridView 控件中自定义数据格式设置
下面的代码示例演示如何实现 DataGridView.CellFormatting 事件的处理程序,该事件根据单元格的列和值更改单元格的显示方式。
包含负数的 Balance
列中的单元格的背景颜色设为红色。 也可将这些单元格的格式设置为货币,以显示负值两边的括号。 有关详细信息,请参阅如何:设置 Windows 窗体 DataGridView 控件中的数据格式。
Priority
列中的单元格显示图像以代替对应文本单元格值。 DataGridViewCellFormattingEventArgs 的 Value 属性同时用于获取文本单元格的值以及设置相应的图像显示值。
示例
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
编译代码
此示例需要:
对 System、System.Drawing 和 System.Windows.Forms 程序集的引用。
名为
highPri.bmp
、mediumPri.bmp
和lowPri.bmp
的 Bitmap 图像,这些图像与可执行文件驻留在相同的目录中。
另请参阅
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