How to Restrict a Windows Forms TextBox to Accept Only Integer Input?

Implement the numerical input verification in the Windows window application

Question:

In the Windows window application, how to configure the text box to accept only the integer value? Ideally, an invalid character input should be ignored or marked immediately.

Solution:

Method 1: Use Numericupdown control

Consider using Numericupdown control, it provides a built -in numerical input filtering function. It also easily uses keyboard arrows to increase and decreases. Method 2: Processing the keyboard incident

For more common solutions, process keyboard events to verify input. The following is an example of the code processing program on the two events on TextBox:

You can customize this code according to specific needs:

If the decimal bit is not allowed, please remove the check of '.'.

<code class="language-c#">private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar) &&
        (e.KeyChar != '-')) //允许负数
    {
        e.Handled = true;
    }
}</code>

If the negative value is allowed, please add a check of '-'.

Set TextBox1.maxLength to limit the number of numbers that allow allowed to be allowed. This prevents the input from being too long.
• Through the above methods, you can effectively limit the Windows window TextBox control only to receive an integer input and provide a better user experience.

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