VB.Net验证：检查文本是否仅包含字母

Question

Need to know how to validate a Text Box's text to make sure it contains ONLY letters without spaces.

I was hoping some sort of functions exists which could help me, something like "IsString" or something.

Answer 1

Use a Regular Expression

if System.Text.RegularExpressions.Regex.IsMatch(TextBox.Text, "^[A-Za-z]+$")) ...

Edit

The ^ $ character are anchors ; they mean match the start and end-of-line respectively and can be used to prevent sub-string/partial matches.

Eg The regex X would match "X" and "AAAXAAA" but ^X$ only matches "X" as its value can be thought of as "<start of line>X<end of line>"

Answer 2

This will prevent anything from being typed into the TextBox except letters.

Private Sub TextBox_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox.KeyPress
    If Not Char.IsLetter(e.KeyChar) Then e.Handled = True  'ignore everything but letter keys
End Sub

Answer 3

您可以使用正则表达式，如下所示：

Return (New System.Text.RegularExpressions.Regex("^[a-zA-Z]{1,}$")).IsMatch(testValue)

Answer 4

To make it simple:

Char.isletter(textboxname)

If char.isletter(textboxname)=false then
Msgbox(error message)
Textboxname.clear()
Textboxname.focus()
End if