Question

我想要2个类（1个Form类）在表单类中，我将Another Class称为void。有用我想用标签和文本框（在第二类脚本中）做thigs 我看到了How to change a label from another class? c# windows forms visual studio 和我的代码：

`private new void Enter(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar == Convert.ToChar(Keys.Enter))
            {
                Commands.OnCommand();`

其他课程：

public static void OnCommand()
    {
        Form1 frm = new Form1();
        if (frm.code.Text.Contains("end") && frm.code.TextLength == 4)
        {
            if (MessageBox.Show("Close?", "Close window?", MessageBoxButtons.YesNo) == DialogResult.Yes)
            {
                frm.Close();
            }
            else
            {
                frm.output.Text = (frm.output.Text + "\nClosing closed").ToString();
                frm.code.Clear();
            }
        }
        else
        {
            MessageBox.Show("test");
            frm.output.Text = (frm.output.Text + "\nI don't understand ... ").ToString();
            frm.code.Clear();
        } /**/

它只显示消息框 ....我认为错误在于声明form1

Answer 1

您必须传递对原始表单的引用，而不是创建它的新实例：

private new void Enter(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == Convert.ToChar(Keys.Enter))
    {
        Commands.OnCommand(this);



public static void OnCommand(Form1 frm)
{
    if (frm.code.Text.Contains("end") && frm.code.TextLength == 4)
    {

话虽如此，我认为将整个Form的引用发送到另一种方法是不好的做法。相反，尝试重新构建它，以便只传入方法所需的值（如code.Text），并让它返回表单需要显示的值。

private new void Enter(object sender, KeyPressEventArgs e)
{
    if (e.KeyChar == Convert.ToChar(Keys.Enter))
    {
        string message = Commands.OnCommand(code.Text);

        if (message == "")
        {
            Close();
        }
        else
        {
            frm.output.Text = frm.output.Text + message;
            frm.code.Clear();
        }



public static void OnCommand(string code)
{
    if (code.Contains("end") && code.Length == 4)
    {
        if (MessageBox.Show("Close?", "Close window?", MessageBoxButtons.YesNo) == DialogResult.Yes)
            return "";
        else
            return "Closing closed";
    }
    else
    {
        MessageBox.Show("test");
        return "I don't understand ... ";
    }

来自C＃中另一个类的对象

1 个答案: