Question

i) 使用另一种形式的形式存在问题

http://www.hchr.org。

i coded like this: (i entered 123 in textbox1)

public class Form1 : Form
{
    private string user_code;

  public string UserCode
    {
        get { return user_code; }
    }

    public bool LoginUser()
    {
   user_code = null;


    if(textBox1.Text=="123"){
          user_code="usercode";
             }
         * 
         */
    }
}

表格2:

          Form1 form1 = new Form1();
          form1.LoginUser();

        MessageBox.Show(form1.UserName);

now output is an empty string,i checked with breakpoint and i saw that when i call loginuser in form2 the value in textbox1 become empty and if condition become false what do you think about problem??

Answer 1

我在

Solution 1 is for ASP.NET, and as I understand it, this is a Windows Form App. So in that case, the easiest way to do this is to just pass a reference from form 1 to form 2 like so:

表格1:

private void button1_Click(object sender, EventArgs e) { Form2 a = new Form2(this); a.Show(); this.Hide(); }

表格2:

public partial class Form2 : Form { Form1 mainForm; public Form2(Form1 mainForm) { InitializeComponent(); this.mainForm = mainForm; } private void button1_Click(object sender, EventArgs e) { mainForm.Show(); this.Hide(); } }

在打上<条码>的时,再用第2条:

The form will still exist in memory it will only be hidden from the user. If this is what you intended, then that is fine. However, if you want to dispose of the form 2, call this.Close() instead.

Answer 2

页: 1

当你履行具有重大参数的职能时,你必须把这一参数作为<>>>out/strong>。

objfrm1.loginuser(out U, out v, out w, out a,out b, out c);

但它将更好地利用公共财产,而不是排除参数。

例如:

public class Form1 : Form
    {
        private string user_pass;
        private string user_name;
        private bool insert_ability;
        private bool update_ability;
        private bool delete_ability;

        public string UserPass
        {
            get { return user_pass; }
        }

        public string UserName
        {
            get { return user_name; }
        }

        public bool InsertAbility
        {
            get { return insert_ability; }
        }

        public bool UpdateAbility
        {
            get { return update_ability; }            
        }

        public bool DeleteAbility
        {
            get { return delete_ability; }           
        }

        public bool LoginUser()
        {
            /*
              Your code here
              user_pass = "userpass";
              user_name = "username";
              insert_ability = true;

              update_ability = false;
              delete_ability = false;
             * 
             */
        }
    }

使用:

Form1 form1 = new Form1();
            form1.LoginUser();

            MessageBox.Show(form1.UserName);

P.S. 和P.S.一样,请永远不使用诸如u、v、w、a、b、c等变名。这种做法是错误的。

Answer 3

根据你的代码,我假定在某人进入用户名和密码时采用这种方法。在不了解更多数据读取器或文本箱子的情况下,我想到的是,在第一个文本箱中,这一呼吁会失败,从而退回空洞。你们是否试图确定文本框,或者在把方法称作形式1之前,如何更好地将案文与你从表2中确定的财产联系起来?

EDIT: Added Code based on your update to show what I mean. I have marked the changes to your code.

public class Form1 : Form
{
    private string user_code;

  public string UserCode
    {
        get { return user_code; }
    }

    private string _testData;                //THIS IS NEEDED
    public string TestData                   //THIS IS NEEDED
    {
        set { _testData = value;}        //THIS IS NEEDED
    }

    public bool LoginUser()
    {
        user_code = null;
        if(textBox1.Text=="123" || TestData=="123")   //THIS IS NEEDED
        {
            user_code="usercode";
        }
    }
}

表格2:

Form1 form1 = new Form1();
form1.TestData = "123";  //THIS IS NEEDED
form1.LoginUser();

MessageBox.Show(form1.UserName);

Answer 4

After editing your code, it does not compile again.
Are you sure you posted your real code?

问题在于:

if(textBox1.Text==123)

<代码>TextBox.Text is a string property,123 is int.

您不能直接比较<条码>、<条码>和<条码>。

因此,你想要做些什么?

Do you want open the Form1 from Form2, type username and password on textboxes in Form1 and pass it into Form2, Right?

EDIT: Your solution

class FormLogin : Form
    {
        public string UserName
        {
            get { return textBoxUserName.Text; }
            set { textBoxUserName.Text = value; }
        }

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

        public FormLogin()
        {
            this.Closing += new System.ComponentModel.CancelEventHandler(FormLogin_Closing);
        }

        void FormLogin_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            if (this.DialogResult == DialogResult.Cancel) return;

            if (!LoginUser(UserName, Password))
            {
                MessageBox.Show("Username or password is incorrect");
                e.Cancel = true;
            }

        }

        bool LoginUser(string userName, string password)
        {
            // check login and password in database for example

            return true;
        }
    }

    class Form3 :Form
    {
        void LoginButtonClick()
        {
            FormLogin formLogin = new FormLogin();
            formLogin.UserName = "LastUserName";
            //uncomment if you want hide main form
            //this.Hide(); 
            if (formLogin.ShowDialog() == DialogResult.OK)
            {
                MessageBox.Show(string.Format("Congratulation! You are logged as {0}", formLogin.UserName));
            }

            //this.Show();
        }
    }

Don t forget add two buttons on FormLogin: OK with DialogResult property OK and Cancel with DialogResult Cancel.

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