DataGridView 控件是一个 Windows 窗体控件，它允许您自定义和编辑表格数据。它提供了许多属性、方法和事件来自定义其外观和行为。在本文中，我们将讨论一些常见问题及其解决方案。这些问题来自各种来源，包括一些新闻组、MSDN 网站以及一些由我在 MSDN 论坛上解答的问题。
技巧 1 – 填充 DataGridView
在这个简短的代码片段中，我们将使用 LoadData() 方法填充 DataGridView。此方法使用 SqlDataAdapter 填充 DataSet。然后将 DataSet 中的“Orders”表绑定到 BindingSource 组件，这使我们能够灵活地选择/修改数据位置。
C#
public partial class Form1 : Form
{
private SqlDataAdapter da;
private SqlConnection conn;
BindingSource bsource = new BindingSource();
DataSet ds = null;
string sql;
public Form1()
{
InitializeComponent();
}
private void btnLoad_Click(object sender, EventArgs e)
{
LoadData();
}
private void LoadData()
{
string connectionString = "Data Source=localhost;Initial Catalog=Northwind;" + "Integrated Security=SSPI;";
conn = new SqlConnection(connectionString);
sql = "SELECT OrderID, CustomerID, EmployeeID, OrderDate, Freight," + "ShipName, ShipCountry FROM Orders";
da = new SqlDataAdapter(sql, conn);
conn.Open();
ds = new DataSet();
SqlCommandBuilder commandBuilder = new SqlCommandBuilder(da);
da.Fill(ds, "Orders");
bsource.DataSource = ds.Tables["Orders"];
dgv.DataSource = bsource;
}
}
VB.NET
Public Partial Class Form1
Inherits Form
Private da As SqlDataAdapter
Private conn As SqlConnection
Private bsource As BindingSource = New BindingSource()
Private ds As DataSet = Nothing
Private sql As String
Public Sub New()
InitializeComponent()
End Sub
Private Sub btnLoad_Click(ByVal sender As Object, ByVal e As EventArgs)
LoadData()
End Sub
Private Sub LoadData()
Dim connectionString As String = "Data Source=localhost;Initial Catalog=Northwind;" & "Integrated Security=SSPI;"
conn = New SqlConnection(connectionString)
sql = "SELECT OrderID, CustomerID, EmployeeID, OrderDate, Freight," & "ShipName, ShipCountry FROM Orders"
da = New SqlDataAdapter(sql, conn)
conn.Open()
ds = New DataSet()
Dim commandBuilder As SqlCommandBuilder = New SqlCommandBuilder(da)
da.Fill(ds, "Orders")
bsource.DataSource = ds.Tables("Orders")
dgv.DataSource = bsource
End Sub
End Class
技巧 2 – 更新 DataGridView 中的数据并将更改保存到数据库中
编辑单元格中的数据后，如果您想在数据库中永久更新更改，请使用以下代码：
C#
private void btnUpdate_Click(object sender, EventArgs e)
{
DataTable dt = ds.Tables["Orders"];
this.dgv.BindingContext[dt].EndCurrentEdit();
this.da.Update(dt);
}
VB.NET
Private Sub btnUpdate_Click(ByVal sender As Object, ByVal e As EventArgs)
Dim dt As DataTable = ds.Tables("Orders")
Me.dgv.BindingContext(dt).EndCurrentEdit()
Me.da.Update(dt)
End Sub
技巧3 – 在 DataGridView 中删除行之前显示确认框
处理 UserDeletingRow 事件，向用户显示确认框。如果用户确认删除，则删除该行。如果用户点击“取消”，则设置 e.cancel = true，取消行删除。
C#
private void dgv_UserDeletingRow(object sender, DataGridViewRowCancelEventArgs e)
{
if (!e.Row.IsNewRow)
{
DialogResult res = MessageBox.Show("Are you sure you want to delete this row?", "Delete confirmation",
MessageBoxButtons.YesNo, MessageBoxIcon.Question);
if (res == DialogResult.No)
e.Cancel = true;
}
}
VB.NET
Private Sub dgv_UserDeletingRow(ByVal sender As Object, ByVal e As DataGridViewRowCancelEventArgs)
If (Not e.Row.IsNewRow) Then
Dim res As DialogResult = MessageBox.Show("Are you sure you want to delete this row?", "Delete confirmation", MessageBoxButtons.YesNo, MessageBoxIcon.Question)
If res = DialogResult.No Then
e.Cancel = True
End If
End If
End Sub
技巧 4 – 如何自动调整 DataGridView 中的列宽
下面的代码片段首先自动调整列的大小以适应其内容。然后将 AutoSizeColumnsMode 设置为“DataGridViewAutoSizeColumnsMode.AllCells”枚举值，以便在数据发生变化时自动调整列的宽度。
C#
private void btnResize_Click(object sender, EventArgs e)
{
dgv.AutoResizeColumns();
dgv.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;
}
VB.NET
Private Sub btnResize_Click(ByVal sender As Object, ByVal e As EventArgs)
dgv.AutoResizeColumns()
dgv.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells
End Sub
技巧 5 - 在 DataGridView 中选择并突出显示整行
C#
int rowToBeSelected = 3; // third row
if (dgv.Rows.Count >= rowToBeSelected)
{
// Since index is zero based, you have to subtract 1
dgv.Rows[rowToBeSelected - 1].Selected = true;
}
VB.NET
Dim rowToBeSelected As Integer = 3 ' third row
If dgv.Rows.Count >= rowToBeSelected Then
' Since index is zero based, you have to subtract 1
dgv.Rows(rowToBeSelected - 1).Selected = True
End If
技巧 6 - 如何以编程方式滚动到 DataGridView 中的某一行
DataGridView 有一个名为 FirstDisplayedScrollingRowIndex 的属性，可用于以编程方式滚动到某一行。
C#
int jumpToRow = 20;
if (dgv.Rows.Count >= jumpToRow && jumpToRow >= 1)
{
dgv.FirstDisplayedScrollingRowIndex = jumpToRow;
dgv.Rows[jumpToRow].Selected = true;
}
VB.NET
Dim jumpToRow As Integer = 20
If dgv.Rows.Count >= jumpToRow AndAlso jumpToRow >= 1 Then
dgv.FirstDisplayedScrollingRowIndex = jumpToRow
dgv.Rows(jumpToRow).Selected = True
End If
技巧 7 - 计算 DataGridView 中的列总数并显示在文本框中
一个常见的需求是计算货币字段的总计并将其显示在文本框中。在下面的代码片段中，我们将计算“运费”字段的总计。然后，我们将在显示数据的同时，通过格式化结果（观察ToString( "c" ) ）将数据显示在文本框中，该文本框会显示特定于文化的货币。
C#
private void btnTotal_Click(object sender, EventArgs e)
{
if(dgv.Rows.Count > 0)
txtTotal.Text = Total().ToString("c");
}
private double Total()
{
double tot = 0;
int i = 0;
for (i = 0; i < dgv.Rows.Count; i++)
{
tot = tot + Convert.ToDouble(dgv.Rows[i].Cells["Freight"].Value);
}
return tot;
}
VB.NET
Private Sub btnTotal_Click(ByVal sender As Object, ByVal e As EventArgs)
If dgv.Rows.Count > 0 Then
txtTotal.Text = Total().ToString("c")
End If
End Sub
Private Function Total() As Double
Dim tot As Double = 0
Dim i As Integer = 0
For i = 0 To dgv.Rows.Count - 1
tot = tot + Convert.ToDouble(dgv.Rows(i).Cells("Freight").Value)
Next i
Return tot
End Function
技巧 8 - 更改 DataGridView 中的标题名称
如果从数据库检索的列没有有意义的名称，我们始终可以选择更改标题名称，如下段所示：
C#
private void btnChange_Click(object sender, EventArgs e)
{
dgv.Columns[0].HeaderText = "MyHeader1";
dgv.Columns[1].HeaderText = "MyHeader2";
}
VB.NET
Private Sub btnChange_Click(ByVal sender As Object, ByVal e As EventArgs)
dgv.Columns(0).HeaderText = "MyHeader1"
dgv.Columns(1).HeaderText = "MyHeader2"
End Sub
技巧 9 - 更改 DataGridView 中单元格、行和边框的颜色
C#
private void btnCellRow_Click(object sender, EventArgs e)
{
// Change ForeColor of each Cell
this.dgv.DefaultCellStyle.ForeColor = Color.Coral;
// Change back color of each row
this.dgv.RowsDefaultCellStyle.BackColor = Color.AliceBlue;
// Change GridLine Color
this.dgv.GridColor = Color.Blue;
// Change Grid Border Style
this.dgv.BorderStyle = BorderStyle.Fixed3D;
}
VB.NET
Private Sub btnCellRow_Click(ByVal sender As Object, ByVal e As EventArgs)
' Change ForeColor of each Cell
Me.dgv.DefaultCellStyle.ForeColor = Color.Coral
' Change back color of each row
Me.dgv.RowsDefaultCellStyle.BackColor = Color.AliceBlue
' Change GridLine Color
Me.dgv.GridColor = Color.Blue
' Change Grid Border Style
Me.dgv.BorderStyle = BorderStyle.Fixed3D
End Sub
技巧 10 - 隐藏 DataGridView 中的列
如果您想根据特定条件隐藏某一列，这里有一个代码片段。
C#
private void btnHide_Click(object sender, EventArgs e)
{
this.dgv.Columns["EmployeeID"].Visible = false;
}
VB.NET
Private Sub btnHide_Click(ByVal sender As Object, ByVal e As EventArgs)
Me.dgv.Columns("EmployeeID").Visible = False
End Sub
技巧 11 - 处理 DataGridView 中 ComboBox 的 SelectedIndexChanged
要处理 DataGridViewComboBox 的 SelectedIndexChanged 事件，您需要使用 DataGridView.EditingControlShowing 事件，如下所示。然后，您可以检索组合框的选定索引或选定文本。
C#
private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
ComboBox editingComboBox = (ComboBox)e.Control;
if(editingComboBox != null)
editingComboBox.SelectedIndexChanged += new System.EventHandler(this.editingComboBox_SelectedIndexChanged);
}
private void editingComboBox_SelectedIndexChanged(object sender, System.EventArgs e)
{
ComboBox comboBox1 = (ComboBox)sender;
// Display index
MessageBox.Show(comboBox1.SelectedIndex.ToString());
// Display value
MessageBox.Show(comboBox1.Text);
}
VB.NET
Private Sub dataGridView1_EditingControlShowing(ByVal sender As Object, ByVal e As DataGridViewEditingControlShowingEventArgs)
Dim editingComboBox As ComboBox = CType(e.Control, ComboBox)
If Not editingComboBox Is Nothing Then
AddHandler editingComboBox.SelectedIndexChanged, AddressOf editingComboBox_SelectedIndexChanged
End If
End Sub
Private Sub editingComboBox_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs)
Dim comboBox1 As ComboBox = CType(sender, ComboBox)
' Display index
MessageBox.Show(comboBox1.SelectedIndex.ToString())
' Display value
MessageBox.Show(comboBox1.Text)
End Sub
技巧 12 - 更改 DataGridView 中交替行的颜色
C#
private void btnAlternate_Click(object sender, EventArgs e)
{
this.dgv.RowsDefaultCellStyle.BackColor = Color.White;
this.dgv.AlternatingRowsDefaultCellStyle.BackColor = Color.Aquamarine;
}
VB.NET
Private Sub btnAlternate_Click(ByVal sender As Object, ByVal e As EventArgs)
Me.dgv.RowsDefaultCellStyle.BackColor = Color.White
Me.dgv.AlternatingRowsDefaultCellStyle.BackColor = Color.Aquamarine
End Sub
技巧 13 - 在 DataGridView 中格式化数据
DataGridView 公开了一些属性，使您能够格式化数据，例如以特定文化的货币显示货币列或以所需的格式显示空值等等。
C#
private void btnFormat_Click(object sender, EventArgs e)
{
// display currency in culture-specific currency for
this.dgv.Columns["Freight"].DefaultCellStyle.Format = "c";
// display nulls as 'NA'
this.dgv.DefaultCellStyle.NullValue = "NA";
}
VB.NET
Private Sub btnFormat_Click(ByVal sender As Object, ByVal e As EventArgs)
' display currency in culture-specific currency for
Me.dgv.Columns("Freight").DefaultCellStyle.Format = "c"
' display nulls as 'NA'
Me.dgv.DefaultCellStyle.NullValue = "NA"
End Sub
技巧 14 – 更改 DataGridView 中的列顺序
要更改列的顺序，只需将 DataGridView 的 DisplayIndex 属性设置为所需的值。请记住，索引从零开始。
C#
private void btnReorder_Click(object sender, EventArgs e)
{
dgv.Columns["CustomerID"].DisplayIndex = 5;
dgv.Columns["OrderID"].DisplayIndex = 3;
dgv.Columns["EmployeeID"].DisplayIndex = 1;
dgv.Columns["OrderDate"].DisplayIndex = 2;
dgv.Columns["Freight"].DisplayIndex = 6;
dgv.Columns["ShipCountry"].DisplayIndex = 0;
dgv.Columns["ShipName"].DisplayIndex = 4;
}
VB.NET
Private Sub btnReorder_Click(ByVal sender As Object, ByVal e As EventArgs)
dgv.Columns("CustomerID").DisplayIndex = 5
dgv.Columns("OrderID").DisplayIndex = 3
dgv.Columns("EmployeeID").DisplayIndex = 1
dgv.Columns("OrderDate").DisplayIndex = 2
dgv.Columns("Freight").DisplayIndex = 6
dgv.Columns("ShipCountry").DisplayIndex = 0
dgv.Columns("ShipName").DisplayIndex = 4
End Sub
我希望这篇文章对您有用，并感谢您的阅读。
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