CODEWITHSUNDEEP
c#
Vivian
Vivian

Reputation: 1061

How to only allow long series of hex byte entries into textbox by user only?

I've done some googling and found this relevant here but its only for masktextbox how do I do it for textbox instead?

For instance, 24 hex byte entries xx xx xx xx xx xx xx xx xx xx xx xx where x is 0-9, a-f ,A-F.

After which, for every group of 2 hex value is converted to its decimal equivalent to be displayed into another textbox? How to do that?

Upvotes: 0

Views: 219

Answers (1)

Matthew Watson
Matthew Watson

Reputation: 109567

This is a bit hacky, but it seems to work.

Add a TextChanged and a KeyPress handler for your text box as follows (this code assumes that the text box is called textBox1 - obviously you should substitute your own):

void textBox1_TextChanged(object sender, EventArgs e)
{
    int caret = textBox1.SelectionStart;
    bool atEnd = caret == textBox1.TextLength;
    textBox1.Text = sanitiseText(textBox1.Text);
    textBox1.SelectionLength = 0;
    textBox1.SelectionStart = atEnd ? textBox1.TextLength : caret;
}

void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (!isHexDigit(e.KeyChar) && e.KeyChar != '\b')
        e.Handled = true;
}

string sanitiseText(string text)
{
    char[] result = new char[text.Length*2];

    int n = 0;

    foreach (char c in text)
    {
        if ((n%3) == 2)
            result[n++] = ' ';

        if (isHexDigit(c))
            result[n++] = c;
    }

    return new string(result, 0,  n);
}

bool isHexDigit(char c)
{
    return "0123456789abcdef".Contains(char.ToLower(c));
}

As for your second question: That's a different question and therefore you should post a separate question for it.

Upvotes: 1

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