How to stop people from entering a certain charaters in a row in visual basic

Question

My problem is I want to block people from putting certain names. Currently I was putting an if statement. The thing is they can simply change the lowercase letter to A Upper-case letter and then they'd be able to use the name But with an Uppercase B. How can I make it so they can't use the same characters in a row, So it wouldn't matter if they made it a lowercase b or an Uppercase B

Private Sub GhostButton1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles GhostButton1.Click

    Try
        DownloadResponse = GetResponse.DownloadString("http://Example.com/target=" & GhostTextBox1.Text)
        FormatResponse = DownloadResponse.Split(New Char() {ControlChars.Lf}, StringSplitOptions.RemoveEmptyEntries)
        RichTextBox1.Text = FormatResponse(0)
        If GhostTextBox1.Text = "buster3636" Then RichTextBox1.Text = "You can not put this name"

there is probably a string_to_lower case function that will help you out so the case of the entry won't matter — nathan hayfield, Feb 26 '13 at 22:08

score 2 · Answer 1 · edited Feb 26 '13 at 22:18

2

Use StringComparison.OrdinalIgnoreCase in Equals

If GhostTextBox1.Text.Equals("buster3636", StringComparison.OrdinalIgnoreCase) Then
    RichTextBox1.Text = "You can not put this name"
End If

If one or both could also be Nothing which could cause a NullReferenceException i would prefer:

StringComparer.OrdinalIgnoreCase.Equals(GhostTextBox1.Text, "buster3636")

edited Feb 26 '13 at 22:18

Jim Lewis

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answered Feb 26 '13 at 22:09

Tim Schmelter

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score 0 · Answer 2 · answered Feb 26 '13 at 22:09

0

A simple way would be to use ToLower(...):

If GhostTextBox1.Text.ToLower() = "buster3636" ...

answered Feb 26 '13 at 22:09

Paul Grimshaw

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fair point, but in a simple English application ToLower(..) would suffice. – Paul Grimshaw Feb 26 '13 at 22:15
Why should i use code which could fail later when it's also less efficient? If you want to use this trick anyway i would prefer `ToUpperInvariant`. – Tim Schmelter Feb 26 '13 at 22:19

How to stop people from entering a certain charaters in a row in visual basic

2 Answers2