Question

我正在使用WinForms和Console Apps学习C＃。我在访问另一个表单变量时遇到问题。我没有声明新的表单对象，而是意识到要使用另一种形式的变量，我需要使用包含变量的相同表单实例。更改我的表单后，我在Program.cs文件中收到一个错误，我似乎无法修复。我对表格中的C＃很新，所以如果这是noob错误，请提前抱歉。声明类的对象对我来说是新的：X

以下是表单背后的代码，以便您更好地理解：

frmOptions：

public partial class frmOptions : Form
    {
        frmHelp frmHelp1;

        public frmOptions(frmHelp frmHelp1)
        {
            InitializeComponent();
        }

        private void tbnDisplayHelp_Click(object sender, EventArgs e)
        {
            //frmHelp frmHelp = new frmHelp();        //Declare a new object for the Help form so it can be accessed
            frmHelp1.bAccessedFromForm = true;
            this.Close();
            frmHelp1.Show();
        }

frmHelp：

public partial class frmHelp : Form
{
    frmOptions frmOptions1;
    frmLoginCreate frmLoginCreate1;

    public bool bAccessedFromForm = false;

    public frmHelp(frmOptions frmOptions1, frmLoginCreate frmLoginCreate)
    {
        InitializeComponent();
    }

    private void btnOK_Click(object sender, EventArgs e)
    {
        //frmLoginCreate frmLoginCreate1 = new frmLoginCreate();
        this.Hide();
        frmLoginCreate1.Show();
    }

    private void frmHelp_Load(object sender, EventArgs e)
    {
        if (bAccessedFromForm == true)
        {
            btnOK.Hide();
            btnReturnToForm.Show();
        }
    }

    private void btnReturnToForm_Click(object sender, EventArgs e)
    {
        this.Hide();
        frmOptions1.Show();
        btnOK.Show();
    }
}

这是我的Program.cs文件：

static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new frmHelp());
        }
    }

这是我在program.cs文件中遇到的错误：

没有任何论据符合所要求的形式参数＆＃39; frmOptions1＆＃39; of＆＃39; frmHelp.frmHelp（frmOptions， frmLoginCreate）＆＃39;

Answer 1

您正在尝试创建frmHelp的新实例，但不传递任何参数。

你的frmHelp类只有一个带有两个参数的构造函数：

public frmHelp(frmOptions frmOptions1, frmLoginCreate frmLoginCreate)
{
        InitializeComponent();
}

简单的答案是将之前的内容更改为：

public frmHelp()
{
    InitializeComponent();
}

因为你没有对这两个参数做任何事情

Answer 2

这不直接回答您的问题，但可能有助于您的解决方案;

我更希望使用modal forms而不是普通表格。

例如：（这只是一个展示如何完成的示例）

public class FormMain : Form
{
    // you might 'remember' the previous login name
    private string _previousUsername;

    private void ButtonLogin_Click(object sender, EventArgs e)
    {
        // create the login form
        using(var loginForm = new FormLogin())
        {
            // fillin the previous username
            loginForm.Username = _previousUsername;

            // this will block here, until the loginForm's DialogResult is set
            var result = loginForm.ShowDialog();

            // if the form was closed (other than pressing ok), cancel login
            if(result != DialogResult.OK)
                return;

            // verify loginForm.Username, loginForm.Password
        }
    }

}


public class FormLogin : Form
{
    // wrapper properties, it wraps the textbox.Text,
    // you don't want to expose the textbox directly, you might want to
    // use some other controls in future as editbox, which will change the contract 
    // for classes that are using this control/form, which causes modifying code 
    // on more than one place, (also affects testing again). This way you can keep it 
    // separated. Classes dependend on the FormLogin, shouldn't be dependend
    // on how it is presented.(UI)
    public string Username 
    { 
        get { return textboxUsername.Text; }
        set { textboxUsername.Text = value; }
    }

    public string Password 
    { 
        get { return textboxPassword.Text; }
        set { textboxPassword.Text = value; }
    }

    private void ButtonLogin_Click(object sender, EventArgs e)
    {
        DialogResult = DialogResult.OK;
    }
}

如果您想将数据传递到其他表单，可以使用DataHolder类。

类似的东西：

// dataholder class
public class MyDataHolder
{
    public string UserName { get; set; }
    public int MyId { get; set; }
    public List<double> Whatever { get; set; }
    public DateTime CreatedOn { get; set; }
}

// form1
public class Form1: Form
{
    // a field with a reference to the dataholder
    private MyDataHolder _myData;

    public Form1()
    {
        // create the data
        _myData = new MyDataHolder();
        _myData.UserName = "Unknown";
        _myData.CreatedOn = DateTime.Now;
    }

    private void Button1_Click(object sender, EventArgs e)
    {
        // create the form2 and pass the data
        using(Form2 form2 = new Form2(_myData))
            form2.ShowDialog();
    }
}

public class Form2 : Form
{
    // a field with a reference to the dataholder
    private MyDataHolder _myData;

    public Form2(MyDataHolder myData)
    {
        // don't forget to assign it to the field
        _myData = myData;
    }

    private void Button1_Click(object sender, EventArgs e)
    {
        // show the username
        MessageBox.Show(_myData.UserName);
    }
}

现在两个表单都引用了相同的数据。这样就可以从Form2 Form1上删除Form2的相关性。因此，您也可以在其他表单中重复使用MyDataHolder，只要您将有效Form2传递给Form1，它就会运行。使用Form2的{{1}}和使用Form2的{{1}}为您提供有限的可重用性，您希望重复使用已编写的代码而不是重写它; - ）

我希望这会帮助你完成任务....

访问其他表单变量

2 个答案: