Question

如果首先只取小数，我想验证一个文本框。没有0或任何数字（例如：.5不是0.5）请帮助我。提前致谢

Answer 1

我拿了一个名为TextBox1的文本框，一个名为Button1的按钮在Button1的click事件上编写了以下代码：

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim getstr As String = TextBox1.Text.Substring(0, 1)
        If getstr = "." Then
            MsgBox("Your input's first place is a '.' - validated.")
        End If
    End Sub

Answer 2

这个功能怎么样......

Private Function do_validate(ByRef curr_textbox As TextBox) As Boolean
    Dim to_return As Boolean = False

    Try
        Dim curr_input_text As String = curr_textbox.Text

        If (Len(curr_input_text > 0)) Then
            Dim left_most As String = Mid(curr_input_text, 1, 1)
            If left_most = "." Then
                to_return = True
            End If
        End If

    Catch
    Finally
        Select Case to_return
            Case True
                curr_textbox.BackColor = Color.LightGreen
            Case False
                curr_textbox.BackColor = Color.LightPink
        End Select
    End Try

    Return to_return
End Function

然后可以从TextBox.TextChanged事件调用它，就像这个do_validate（txt_input）一样。它也可以从提交按钮调用，作为验证序列的一部分。

如何验证第一位是仅在vb中的十进制？

2 个答案: