[NET.VB]小问题集锦(供初学者参考)

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声明：

1、所有代码不注明出处的皆为本人所写

2、所有代码均在本机调试通过

3、本贴适用于初学者（本人也是）

4、欢迎各位仁兄斧正，提供想法或代码

5、本人力求每日补充内容

6、非本人同意，请勿转载本人所写的代码

7、各位说要不要上面第6条？

8、哈，声明是这样写的吗，一点都不严肃，也不规范

水如烟 2004.7.19

[控件类]

TreeView

1、给节点加个ToolTip(2004.7.19)

Private tmpTreeNode As TreeNode Private mTreeViewToolTip As New ToolTip

Private Sub TreeView1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles TreeView1.MouseMove Dim mNode As TreeNode mNode = Me.TreeView1.GetNodeAt(e.X, e.Y) '当前没节点 If mNode Is Nothing Then mTreeViewToolTip.SetToolTip(Me.TreeView1, Nothing) Exit Sub End If '超过当前Node的边界 If mNode.Bounds.Right < e.X OrElse mNode.Bounds.Left > e.X Then mTreeViewToolTip.SetToolTip(Me.TreeView1, Nothing) Exit Sub End If '同一个Node If mNode Is tmpTreeNode Then Exit Sub End If mTreeViewToolTip.AutomaticDelay = 500 mTreeViewToolTip.SetToolTip(Me.TreeView1, mNode.Text) tmpTreeNode = mNode End Sub

DataGrid

1、自适应各列长度(2004.7.19)

'定义一个字段信息类Private Class ColumnInfo Public [Name] As String Public [DataType] As String Public MaxWidth As Integer = 0 Public Sub CompareStringLength(ByVal mString As String) Dim mLength As Integer mLength = System.Text.Encoding.Default.GetBytes(mString).Length() If MaxWidth < mLength Then MaxWidth = mLength End Sub Public Function ColumnWidth(ByVal mDataGrid As DataGrid) As Integer Dim mGraphics As Graphics = mDataGrid.CreateGraphics Dim mColWidth As Single mColWidth = mGraphics.MeasureString(New String(CType("A", Char), MaxWidth), mDataGrid.Font).Width + 2 Return CType(mColWidth, Integer) End FunctionEnd Class

Private Sub MakeDataGridAutoExtend(ByVal mDataGrid As DataGrid) '判断mDataGrid数据源类型 '如果绑定的是DataSet或DataViewManager或没有绑定任何数据源，则退出, If TypeOf mDataGrid.DataSource Is System.Data.DataSet OrElse _ TypeOf mDataGrid.DataSource Is System.Data.DataViewManager OrElse _ mDataGrid.DataSource Is Nothing Then Exit Sub '以下分别考虑两种数据源，一是DataView,一是DataTable Dim dt As DataTable If TypeOf mDataGrid.DataSource Is System.Data.DataView Then dt = CType(mDataGrid.DataSource, DataView).Table Else dt = CType(mDataGrid.DataSource, DataTable) End If '取各字段信息 Dim mColumnInfo(dt.Columns.Count - 1) As ColumnInfo Dim i As Integer = 0 Dim mColumn As DataColumn For Each mColumn In dt.Columns Dim mInfo As New ColumnInfo With mInfo .Name = mColumn.ColumnName .DataType = mColumn.DataType.ToString .CompareStringLength( mColumn.ColumnName) End With mColumnInfo(i) = mInfo i += 1 Next '取各字段的最大长度 Dim mRow As DataRow For Each mRow In dt.Rows For i = 0 To dt.Columns.Count - 1 If Not IsDBNull(mRow(i)) Then mColumnInfo(i).CompareStringLength(CType(mRow(i), String)) End If Next Next '建DataGridTableStyle Dim ts As New DataGridTableStyle ts.MappingName = dt.TableName For i = 0 To dt.Columns.Count - 1 If mColumnInfo(i).DataType.Equals("System.Boolean") Then '这是Boolean字段 Dim blnCol As New DataGridBoolColumn With blnCol .MappingName = mColumnInfo(i).Name .HeaderText = mColumnInfo(i).Name .Width = mColumnInfo(i).ColumnWidth(mDataGrid) .NullText = "" End With ts.GridColumnStyles.Add(blnCol) Else '非Boolean字段 Dim TxtCol As New DataGridTextBoxColumn With TxtCol .MappingName = mColumnInfo(i).Name .HeaderText = mColumnInfo(i).Name .Width = mColumnInfo(i).ColumnWidth(mDataGrid) .NullText = "" .ReadOnly = False '这里可以设置为只读 .Format = "" '这里可以设置显示格式，要显示日时分秒的就在这设 End With ts.GridColumnStyles.Add(TxtCol) End If Next mDataGrid.TableStyles.Clear() mDataGrid.TableStyles.Add(ts) '至于其它的功能，比如绑定事件之类的，后面再补充End Sub　

'调用Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click MakeDataGridAutoExtend(Me.DataGrid1)End Sub