How Can I Ensure Only Numeric Input in Windows Forms Textboxes?

Windows window text box Digital input verification guidelines

Make sure that the text box accepts only digital characters is the key to verification of the Windows window application data verification. For this reason, you can use a variety of technologies:

<.> 1. Use Numericupdown control

Consider using the Numericupdown control instead of the standard text box. By default, Numericupdown seamlessly filter out non -digital input and provide an intuitive user experience. In addition, it also allows incremental/reduction operations through keyboard shortcut keys.

<.> 2. Filter based on the event

Use event processing procedures to intercept and filter invalid characters in real time. For example, you can implement the following event processing procedures:

: prevent input non -digital characters, except for decimal points.

private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
{
    if (!char.IsControl(e.KeyChar) && !char.IsDigit(e.KeyChar) &&
        (e.KeyChar != '.'))
    {
            e.Handled = true;
    }

    // 只允许一个小数点
    if ((e.KeyChar == '.') && ((sender as TextBox).Text.IndexOf('.') > -1))
    {
        e.Handled = true;
    }
}

: (Here, the

Event processing program code should be added to verify the values ​​after modifying and display the error message when violating the constraints.)
• textBox1_KeyPress
Other precautions:
• textBox1_TextChanged textBox1_TextChanged
Trip point:

Adjust the event processing logic as required to allow or not allow decimal bits.

Negative value: If your text box allows negative inputs, it should include a negative sign (-) check.

Input limit:
• Set the attribute of the text box to limit the number of digits that the user can input.

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