VB.NET常用技巧代码

1. 单元格相互计算关键字： .Focused Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged, TextBox2.TextChanged If TextBox1.Focused Then TextBox2.Text = Val(TextBox1.Text) * 3 ElseIf TextBox2.Focused Then TextBox1.Text = Val(TextBox2.Text) / 3 End If End Sub2. 对比两个数据的字符大小关键字： StrComp(string1,string2) Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click Label4.Text = StrComp(TextBox5.Text, TextBox6.Text)string1 string2，返回1 End Sub3. 对应匹配关键字： While.End While Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click Dim city() As String = 北京, 上海, 天津, 广州, 哈尔滨, 长春, 沈阳, 西安, 兰州, 银川, 太原 Dim no() As String = 010, 021, 022, 020, 0451, 0431, 024, 029, 0931, 0951, 0351 Dim i% = 0 While (i UBound(no) And StrComp(no(i), TextBox7.Text) 0) i = i + 1 End While If StrComp(no(i), TextBox7.Text) = 0 Then Label5.Text = 对应城市为： & city(i) Else Label5.Text = 没有所对应城市 End If End Sub4. 随机数生成、在原基础扩增数组、逐行扩增文本显示关键字： Int(Rnd() * 80) + 20、ReDim Preserve score(n + 1)、mystr = mystr + String(i) & Chr(13) & Chr(10) Private Sub Button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button5.Click Dim n%, score!(), i%, sum! Dim mystr As String = n = Val(TextBox8.Text) ReDim score(n - 1) For i = 0 To n - 1 score(i) = Int(Rnd() * 80) + 20 sum = sum + score(i) Next ReDim Preserve score(n + 1) score(n) = sum / n score(n)平均数计算，score(n+1)计算超过平均数的个数 For i = 0 To n - 1 If score(i) score(n) Then score(n + 1) = score(n + 1) + 1 End If Next For i = 0 To n - 1 mystr = mystr + Str(score(i) & Chr(13) & Chr(10) Next TextBox9.Text = mystr TextBox10.Text = score(n) TextBox11.Text = score(n + 1) End Sub5. 骗过文本框TextChanged事件关键字： Dim a# a = Val(TextBox1.Text) TextBox1.Text = TextBox1.Text = a6. LinkLabel单击后文字切换关键字： 定义全局变量、NotDim judge As Boolean Private Sub LinkLabel1_LinkClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel1.LinkClicked judge = Not judge If judge = False Then LinkLabel1.Text = 温度/ Else LinkLabel1.Text = 温度/ End If End Sub7. 限制文本框数字输入关键字： KeyPress事件、CType(转换类型)、InStr(字符查找)、TextBox1.SelectionStart=0(光标在起始位置)Private Sub T11_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles T11.KeyPress, T12.KeyPress, T13.KeyPress Dim bool0 As Boolean, bool1 As Boolean, bool2 As Boolean, bool3 As Boolean 对输入的小数点进行判断 If InStr(CType(sender, TextBox).Text, .) 0 Then bool0 = True 如果已经输入了一个小数点，则第二个小数点不能再输入 ElseIf CType(sender, TextBox).Text Like *e = True Or CType(sender, TextBox).Text Like *e* = True Then If CType(sender, TextBox).SelectionStart = InStr(CType(sender, TextBox).Text, e) Then bool0 = True 如果没有输入小数点，当出现如“1e”字符时，则光标从“e”往后不能输入小数点；如果出现如“1e32”，则“e”后面的不能输入小数点 ElseIf Mid(CType(sender, TextBox).Text, 1, 1) = - Then If CType(sender, TextBox).SelectionStart = 0 Then bool0 = True 如果有负号，则负号前不能输入小数点 End If End If ElseIf Mid(CType(sender, TextBox).Text, 1, 1) = - Then If CType(sender, TextBox).SelectionStart = 0 Then bool0 = True 如果有负号，则负号前不能输入小数点 End If Else bool0 = False End If 对输入e进行判断 If InStr(CType(sender, TextBox).Text, e) 0 Then bool1 = True 如果已经输入一个e，则第二个e不能再输入 ElseIf CType(sender, TextBox).Text = Then bool1 = True 如果文本框为空值，则不能以e打头 ElseIf CType(sender, TextBox).Text = . Or CType(sender, TextBox).Text = -. Or CType(sender, TextBox).Text = - Then bool1 = True 如果文本框第一个字符为小数点、负号、“-.”，则不能紧接着输入e ElseIf CType(sender, TextBox).Text Like * Then If CType(sender, TextBox).SelectionStart Len(CType(sender, TextBox).Text) Then bool1 = True 如果文本框已经有字符，则只有当光标在字符串最右侧时可以输入e End If Else bool1 = False End If 对负号输入判断 If CType(sender, TextBox).Text = Then bool2 = True 如果文本框为空值，则可以输入负号 ElseIf CType(sender, TextBox).Text Like *e = True Then If CType(sender, TextBox).SelectionStart = InStr(CType(sender, TextBox).Text, e) Then bool2 = True 如果文本框当前字符如“1e”，紧接着可以输入负号 ElseIf CType(sender, TextBox).SelectionStart = 0 And Mid(CType(sender, TextBox).Text, 1, 1) - Then bool2 = True 如果文本框当前字符如“1e”，光标在起始位置并且第一个字符不是负号时，可以在起始位置输入负号 End If ElseIf CType(sender, TextBox).Text Like *e#* = True Then If CType(sender, TextBox).SelectionStart = InStr(CType(sender, TextBox).Text, e) Then bool2 = True 如果文本框当前字符如“1e3”，则当光标移到e后面才能输入负号 ElseIf CType(sender, TextBox).SelectionStart = 0 And Mid(CType(sender, TextBox).Text, 1, 1) - Then bool2 = True 如果文本框当前字符如“1e3”，光标在起始位置并且第一个字符不是负号时，可以在起始位置输入负号 End If ElseIf Mid(CType(sender, TextBox).Text, 1, 1) - Then If CType(sender, TextBox).SelectionStart = 0 Then bool2 = True 如果文本框当前第一个字符不是负号，则当光标移动到起始位置时可以输入负号 End If Else bool2 = False End If 对已经输入内容的部分再次输入数字进行判断 If InStr(CType(sender, TextBox).Text, -) 0 Then If CType(sender, TextBox).SelectionStart = 0 Or CType(sender, TextBox).SelectionStart = InStr(2, CType(sender, TextBox).Text, -) - 1 Then bool3 = True 两种情况，一种是负号在前面部分，则负号前不能输入数字；另一种是负号在e后面，负号前不能输入数字 End If Else bool3 = False End If KeyPress事件的核心部分，对文本框仅限制输入数字、小数点、负号、退格键、e，并通过以上的判断来具体体现限制字符输入 If Char.IsDigit(e.KeyChar) Or e.KeyChar = . Or e.KeyChar = Chr(8) Or e.KeyChar = e Then If e.KeyChar = . And bool0 Then e.Handled = True ElseIf e.KeyChar = e And bool1 Then e.Handled = True ElseIf Char.IsDigit(e.KeyChar) And bool3 Then e.Handled = True Else e.Handled = False End If ElseIf e.KeyChar = - And bool2 Then e.Handled = False Else e.Handled = True End If End Sub8. 小数位处理关键字： Format()、递归调用 该函数为格式化数字显示格式函数。示例中浮点数显示最多占9个字符，如-0.000001， 科学计数显示最多占12个字符，如-1.0000e+004。如需修改格式显示，只需修改如 “10000”、“0.0001”、“0.000000”等标识符，注意Select Case的个数。 Function formatdigit$(ByVal a#) Dim b$ = , n% If a 0 Then If a = 10000 Then For n = 1 To 999 If Int(a / 10 n + 0.1) 0 And Int(a / 10 n + 0.1) = 0.0001 And a 10000 Then Select Case a Case Is 10 b = Format(a, 0.000000) Case Is 100 b = Format(a, 0.00000) Case Is 1000 b = Format(a, 0.0000) Case Is 0 And a 0 And Int(a * 10 n + 0.1) 10 Then Exit For End If Next b = Format(a * 10 n, 0.0000) & e- & Format(n, 000) 小于0.0001时以科学计数显示，并保留四位小数 End If ElseIf a = 0 Then b = Format(a, 0.000000) 当数字为零时显示 ElseIf a 0 Then b = - & formatdigit(-a) 递归调用，求小于零的情况 End Ifformatdigit = b End Function9. 对限制字符输入的文本框使用快捷键关键字： e.Control、e.KeyCode Private Sub TextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown, TextBox2.KeyDown, TextBox3.KeyDown If e.Control And e.KeyCode = Keys.A Then CType(sender, TextBox).SelectAll() End If If e.Control And e.KeyCode = Keys.C Then CType(sender, TextBox).Copy() End If If e.Control And e.KeyCode = Keys.V Then CType(sender, TextBox).Paste() End If If e.Control And e.KeyCode = Keys.X Then CType(sender, TextBox).Cut() End If End Sub10. 批量为某一容器中的全部文本框赋值关键字： Control、TypeOf Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim c As Control For Each c In TabControl1.TabPages(0).Controls 这里以TabControl1中的第一个页面为容器 If TypeOf c Is TextBox Then c.Text = End If Next End Sub其实这样操作效率不高 For i = 1 To 3 For Each c1 In Me.Controls For Each c2 In Me.Controls If TypeOf c1 Is TextBox Then If TypeOf c2 Is TextBox Then If c1.Name = T1 & i Then If c2.Name = T2 & i Then c1.Text = i c2.Text = Val(c1.Text) * (i + 1) End If End If End If End If Next Next Next11. 复制光标所在文本框并着色显示关键字： Clipboard.SetText()、GotFocus事件 Dim T As New TextBox Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click If T.Text Then Clipboard.SetText(T.Text, TextDataFormat.Text) Dim c As Control For Each c In Me.Controls If TypeOf c Is TextBox Then If c.Name = T.Name Then c.BackColor = T.BackColor Exit Sub End If End If Next End If End Sub 对单击鼠标后光标所在的文本框复制内容 Private Sub T11_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles T11.GotFocus, T12.GotFocus, T13.GotFocus, T21.GotFocus, T22.GotFocus, T23.GotFocus T.Text = CType(sender, TextBox).Text T.Name = CType(sender, TextBox).Name T.BackColor = Color.DeepPink Dim c As Control For Each c In Me.Controls If TypeOf c Is TextBox Then c.BackColor = Color.Empty 让文本框背景色恢复到原来 End If Next End Sub 对单击鼠标光标所在的文本框又进行了文字编辑的文本框内容复制 Private Sub T11_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles T11.TextChanged, T12.TextChanged, T13.TextChanged, T21.TextChanged, T22.TextChanged, T23.TextChanged Dim c As Control For Each c In Me.Controls If TypeOf c Is TextBox Then If c.Focused Then T.Text = c.Text End If End If NextEnd Sub12. DataGridView控件显示标题行号关键字： DataGridView，RowPostPaint事件 Private Sub DataGridView1_RowPostPaint(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewRowPostPaintEventArgs) Handles DataGridView1.RowPostPaint 通过RowPostPaint事件画行号 Dim rect As New Rectangle(e.RowBounds.Left, e.RowBounds.Top, _ DataGridView1.RowHeadersWidth - 3, e.RowBounds.Height) 定义一个矩形, 矩形边界贴左和上, 矩形的宽度为行标题的高度减去一个数值(这里是) TextRenderer.DrawText(e.Graphics, (e.RowIndex + 1).ToString, _ e.InheritedRowStyle.Font, rect, e.InheritedRowStyle.ForeColor, _ TextFormatFlags.Right Or TextFormatFlags.VerticalCenter) 画文本，文本从开始，字体，前景色都是继承行标题的样式，字体大小（像素） 就是上面定义的矩形大小，字体是右对齐、垂直居中的End Sub13. DataGridView动态添加行并为单元格赋值关键字： .Rows.Add、.Rows(index).Cells(0).Value Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 为Datagridview添加行，并将单元格赋值 Dim index As Integer For index = 0 To 19 index = DataGridView1.Rows.Add 添加行的关键句 DataGridView1.Rows(index).Cells(0).Value = (index + 1).ToString 为单元格赋值，第一列单元格从Cells(0)开始 Next End Sub14. DataGridView设置技巧关键字：是否允许用户添加行：AllowUserToAddRows属性更改背景色(默认是灰黑色)：BackgroundColor属性设置行标题字体样式：ColumnHeaderDefaultCellStyle属性单元格样式设置：DefaultCellStyle属性禁止按列进行排序：进入Columns集合编辑列，更改SortMode属性为NotSortabel设置行标题宽度和列标题高度，并固定：ColumnHeadersHeight + ColumnHeadersHeightSizeMode属性改为DisableResizing；RowHeadersWidth + RowHeadersWidthSizeMode属性改为DisableResizing设置行高并固定：AutoSizeRowsMode设为None，AllowUserToResizeRows属性为False；RowTemplateHeight属性设置高度值，如18列的右侧不显示空白：AutoSizeColumnsMode属性设为Fill选择模式：SelectionMode属性，可设置按列标题选择(ColumnHeadersSelect)不显示编辑图标：ShowEditionIcon属性设置为False让最后一行不显示黑边技巧：DataGridView高度=列标题高度+行高*任意整数+2去除行标题上的小三角形：(代码)DataGridView1.RowHeadersDefaultCellStyle.Padding = New Padding(DataGridView1.RowHeadersWidth)15. DataGridView选中的单元格内容删除关键字： IsDBNull() Private Sub DataGridView1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles DataGridView1.KeyDown 用删除键或退格键删除内容 If e.KeyCode = Keys.Delete Or e.KeyCode = Keys.Back Then For Each cell As DataGridViewCell In DataGridView1.SelectedCells If IsDBNull(cell.Value) = False Then cell.Value = DBNull.Value End If Next End IfEnd Sub16. DataGridView添加右键复制菜单关键字： Clipboard.SetDataObject()、GetClipboardContent Private Sub 复制CtrlToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles 复制CtrlToolStripMenuItem.Click If DataGridView1.Focused Then Clipboard.SetDataObject(DataGridView1.GetClipboardContent) ElseIf DataGridView2.Focused Then Clipboard.SetDataObject(DataGridView2.GetClipboardContent) End IfEnd Sub17. 综合运用将Excel表格中的内容导入DataGridView关键字： DataGridView1.Columns.Add()、.Font=New Font(“Arial”, .Font.Size)OpenFileDialog1.Filter = Excle文件(*.xls)|*.xls、SELECT * FROM Sheet1$A1:B65536、Catch End Try Dim wd As Integer = 30 行标题宽度 Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim index As Integer, i As Integer Me.DataGridView1.Columns.Add(column1, X) Me.DataGridView1.Columns.Add(column1, Y) With DataGridView1 .RowHeadersDefaultCellStyle.Padding = New Padding(DataGridView1.RowHeadersWidth) 去除行标题上的小三角形 .AllowUserToAddRows = False .ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.DisableResizing .ColumnHeadersHeight = 20 .RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.DisableResizing .RowHeadersWidth = wd .AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.None .AllowUserToResizeRows = False .AllowUserToResizeColumns = False .RowTemplate.Height = 18 .AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill .ShowEditingIcon = False .ClipboardCopyMode = DataGridViewClipboardCopyMode.EnableWithoutHeaderText .SelectionMode = DataGridViewSelectionMode.RowHeaderSelect .RowHeadersBorderStyle = DataGridViewHeaderBorderStyle.Single With .ColumnHeadersDefaultCellStyle .Font = New Font(Arial, .Font.Size) .Alignment = DataGridViewContentAlignment.MiddleCenter End With With .DefaultCellStyle .Font = New Font(Arial, .Font.Size) .Alignment = DataGridViewContentAlignment.MiddleRight End With End With For i = 0 To DataGridView1.Columns.Count - 1 Me.DataGridView1.Columns(i).SortMode = DataGridViewColumnSortMode.NotSortable Next For index = 0 To 15 index = DataGridView1.Rows.Add Next End Sub Private Sub DataGridView1_RowPostPaint(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewRowPostPaintEventArgs) Handles DataGridView1.RowPostPaint 通过RowPostPaint事件画行号 Dim rect As New Rectangle(e.RowBounds.Left, e.RowBounds.Top, _ DataGridView1.RowHeadersWidth - 1, e.RowBounds.Height) 定义一个矩形, 矩形边界贴左和上, 矩形的宽度为行标题的高度- 一个数值(这里是) TextRenderer.DrawText(e.Graphics, (e.RowIndex + 1).ToString, _ Me.DataGridView1.ColumnHeadersDefaultCellStyle.Font, rect, e.InheritedRowStyle.ForeColor, _ TextFormatFlags.Right Or