根据表格内容，自动调整VB.NET中Datagrid控件单元格宽度

      用Datagrid控件显示表格数据，当表格内容过多时，Datagrid控件单元格宽度并不足以用来完全显示表格中的数据内容。而只有自己每次去拉动分界线，来进行调整。当出现表格字段比较多时，这样做就显得很麻烦。
以下是用程序根据表格内容来自动调整Datagrid控件单元格宽度。
先定义一个Sub过程AutoSizeCol，用来调整Datagrid中的列宽。
如下：
Public Sub AutoSizeCol(ByVal col As Integer)
  Dim width As Single
  width = 0
  Dim numRows As Integer
  numRows = CType(dataGrid1.DataSource, DataTable).Rows.Count
  Dim g As Graphics
  g = Graphics.FromHwnd(dataGrid1.Handle)
  Dim sf As StringFormat
  sf = New StringFormat(StringFormat.GenericTypographic)
  Dim size As SizeF
  Dim i As Integer
  i = 0

  Do While (i < numRows)
    size = g.MeasureString(dataGrid1(i, col).ToString, dataGrid1.Font, 500, sf)
    If (size.Width > width) Then
       width = size.Width
    End If
    i = (i + 1)
    Loop

   g.Dispose()
   dataGrid1.TableStyles("customers").GridColumnStyles(col).Width = CType(width, Integer)

End Sub

现在就可以表格内容来定义整张表所有列的宽度了。如下：
Public Sub AutoSizeTable()
  Dim numCols As Integer
  numCols = CType(dataGrid1.DataSource, DataTable).Columns.Count
  Dim i As Integer
  i = 0
  Do While (i < numCols)
    AutoSizeCol(i)
    i = (i + 1)
  Loop
End Sub

只要使用以上两个Sub过程就可以达到你想要的结果了！

一个完整的实例如下:
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles   MyBase.Load
  Dim connString As String
  connString = "Provider=Microsoft.JET.OLEDB.4.0;data source=northwind.mdb"
  Dim sqlString As String
  sqlString = "SELECT * FROM customers"
  Dim dataAdapter As OleDbDataAdapter
  dataAdapter = Nothing
  Dim _dataSet As DataSet
  _dataSet = Nothing

Try

  Dim connection As OleDbConnection
  connection = New OleDbConnection(connString)

  dataAdapter = New OleDbDataAdapter(sqlString, connection)

  _dataSet = New DataSet
  dataAdapter.Fill(_dataSet, "customers")
  connection.Close()
  Catch ex As Exception
MessageBox.Show("出错！")
  Me.Close()
  Return
End Try
  Dim tableStyle As DataGridTableStyle
  tableStyle = New DataGridTableStyle
  tableStyle.MappingName = "customers"

  dataGrid1.TableStyles.Clear()
  dataGrid1.TableStyles.Add(tableStyle)
  dataGrid1.DataSource = _dataSet.Tables("customers")
End Sub

Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
  AutoSizeTable()
End Sub

Private Sub button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles   button2.Click
  AutoSizeCol(1)
End Sub
 

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