C# Resize textbox to fit content

Question

I\'m writing a program where the user should be able to write text in a textbox. I\'d like the textbox to resize itself, so it fit the content. I\'ve tried the following:

Answer 1

I am adding this answer as I do not see the fixed width aspect of a textbox being discussed in any of the other. If you have a fixed width for your textbox, and you want to adjust only its height you can do something like the following:

Something like this gives the height of the text as how it is drawn in the multiline wordwrapped textbox itself:

SizeF MessageSize = MyTextBoxControl.CreateGraphics()
                                .MeasureString(MyTextBoxControl.Text,
                                                MyTextBoxControl.Font,
                                                MyTextBoxControl.Width, 
                                                new StringFormat(0));

I am not sure what StringFormat should be but the values StringFormatFlags do not seem to apply to a default TextBox make up.

Now with MessageSize.Height you know the height of the text in the textbox.

Answer 2

first, create method to Make the TextBox fit its contents.

private void AutoSizeTextBox(TextBox txt)
{
    const int x_margin = 0;
    const int y_margin = 2;
    Size size = TextRenderer.MeasureText(txt.Text, txt.Font);
    txt.ClientSize =
        new Size(size.Width + x_margin, size.Height + y_margin);
}

then with the TextChanged event handler calls AutoSizeTextBox() function to make the TextBox fit its text when the text changes.

private void txtContents_TextChanged(object sender, EventArgs e)
{
    AutoSizeTextBox(sender as TextBox);
}

That’s all, for more info:

resize-a-textbox-to-fit-its-text

Answer 3

Your binding to the wrong event, and you cannot use the graphics object in the TextChangedEventArgs object.

Try using the TextChanged event. The following snippet is working:

public Form1()
{
    InitializeComponent();

    this.textBox1.TextChanged += new EventHandler(textBox1_TextChanged);
}

void textBox1_TextChanged(object sender, EventArgs e)
{
    System.Drawing.SizeF mySize = new System.Drawing.SizeF();

    // Use the textbox font
    System.Drawing.Font myFont = textBox1.Font;

    using (Graphics g = this.CreateGraphics())
    {
        // Get the size given the string and the font
        mySize = g.MeasureString(textBox1.Text, myFont);
    }

    // Resize the textbox 
    this.textBox1.Width = (int)Math.Round(mySize.Width, 0);
}

}

Answer 4

Did you try to set yourTextBox.AutoSize = true;? This property may be hidden in the GUI designer, but you can set it in the form constructor right after InitializeComponent(); call.