CODEWITHSUNDEEP
c#winforms
JimmyN
JimmyN

Reputation: 599

Keep a certain number of lines in the richtextbox?

I want to keep a certain number of lines in the richtextbox, so I did the following:

    private void txt_Log_TextChanged(object sender, EventArgs e)
    {
        int max_lines = 200;
        if (txt_Log.Lines.Length > max_lines)
        {
            string[] newLines = new string[max_lines];
            Array.Copy(txt_Log.Lines, 1, newLines, 0, max_lines);
            txt_Log.Lines = newLines;
        }
        txt_Log.SelectionStart = txt_Log.Text.Length;
        txt_Log.ScrollToCaret();
    }

But when running my Richtextnbox blinks continuously, so how should I make this smooth ?

Upvotes: 0

Views: 360

Answers (2)

Ryan Naccarato
Ryan Naccarato

Reputation: 1181

One option would be to unhook the listener, perform the update, then re-hook the listener upon exiting the function.

private void txt_Log_TextChanged(object sender, EventArgs e)
{
    txt_Log.TextChanged -= this.txt_Log_TextChanged;

    //make you're updates here...

    txt_Log.TextChanged += this.txt_Log_TextChanged;
}

Upvotes: 1

Dmitry
Dmitry

Reputation: 14059

When you update a value of the txt_Log.Lines property, the txt_Log_TextChanged event fires again.

You could use a bool variable to stop it:

private bool updatingTheText;

private void txt_Log_TextChanged(object sender, EventArgs e)
{
    if (updatingTheText)
        return;

    const int max_lines = 200;
    if (txt_Log.Lines.Length > max_lines)
    {
        string[] newLines = new string[max_lines];
        Array.Copy(txt_Log.Lines, 1, newLines, 0, max_lines);
        updatingTheText = true;  // Disable TextChanged event handler
        txt_Log.Lines = newLines;
        updatingTheText = false; // Enable TextChanged event handler
    }
    txt_Log.SelectionStart = txt_Log.Text.Length;
    txt_Log.ScrollToCaret();
}

Upvotes: 0

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