如何从C#中的Form返回一个值？

// 在Form1中设置DialogResult属性
private void button1_Click(object sender, EventArgs e)
{
    this.DialogResult = DialogResult.OK;
}

// 在主窗体中捕获Form1的DialogResult属性
private void button2_Click(object sender, EventArgs e)
{
    Form1 form1 = new Form1();
    DialogResult result = form1.ShowDialog();
    if (result == DialogResult.OK)
    {
        // 处理返回值
    }
}

// 在Form1中定义自定义事件
public event EventHandler<EventArgs<string>> ValueReturned;

private void button1_Click(object sender, EventArgs e)
{
    if (ValueReturned != null)
    {
        ValueReturned(this, new EventArgs<string>("返回值"));
    }
}

// 在主窗体中订阅自定义事件
private void button2_Click(object sender, EventArgs e)
{
    Form1 form1 = new Form1();
    form1.ValueReturned += (s, args) =>
    {
        string returnValue = args.Value;
        // 处理返回值
    };
    form1.ShowDialog();
}

// 定义委托类型
public delegate void ValueReturnedHandler(string value);

// 在Form1中定义委托属性
public ValueReturnedHandler ValueReturned;

private void button1_Click(object sender, EventArgs e)
{
    if (ValueReturned != null)
    {
        ValueReturned("返回值");
    }
}

// 在主窗体中赋值委托属性
private void button2_Click(object sender, EventArgs e)
{
    Form1 form1 = new Form1();
    form1.ValueReturned = (value) =>
    {
        // 处理返回值
    };
    form1.ShowDialog();
}