numericUpDown1 值超过最大范围后返回的值 （C# Windows 窗体）

一种方法是处理事件。我个人使用的方法是继承它的实例，并将其在 MainForm.Designer.cs 文件中替换为我的自定义类。现在，如果在设计器中将值设置为 10，它将按照您描述的方式运行。KeyDownNumericUpDownMaximum

class NumericUpDownEx : NumericUpDown
{
    // Disable range checking in the base class.
    public NumericUpDownEx()
    {
        base.Maximum = decimal.MaxValue;
        base.Minimum = decimal.MinValue;
    }
    public new decimal Maximum { get; set; } = 100; // Keep default value the same
    public new decimal Minimum { get; set; } = 0;   // Keep default value the same

    protected override void OnKeyDown(KeyEventArgs e)
    {
        base.OnKeyDown(e);
        switch (e.KeyData)
        {
            case Keys.Enter:
                e.Handled = e.SuppressKeyPress = true;
                BeginInvoke((MethodInvoker)delegate
                {
                    // In this case, Designer has set Min = 1, Max = 10
                    if (Value < Minimum || Value > Maximum)
                    {
                        var message = $"Error: '{Value}' is not legal.";
                        Value = 1;
                        MessageBox.Show(message);
                        Focus();
                    }
                    var length = Value.ToString().Length;
                    if (length > 0)
                    {
                        Select(0, length);
                    }
                });
                break;
        }
    }
    .
    .
    .
}

当控件失去焦点时，您还需要执行相同的操作。

    .
    .
    .
    /// <summary>
    ///  The Validating event doesn't always fire when we want it to,
    ///  especially if this is the only control. Do this instead;
    /// </summary>
    protected override void OnLostFocus(EventArgs e)
    {
        base.OnLostFocus(e); 
        OnKeyDown(new KeyEventArgs(Keys.Enter));
    }