与backgroundworker异步打开第二个winform [英] Open a second winform asynchronously with backgroundworker

问题描述

我有一个名为 login 的winform，询问用户名和密码，用数据库检查信息（在线），然后显示
主winform ，但为了避免应用程序冻结，我使用了两个
backgroundworker 。

在我的主winform上，我有几个标签需要连接到数据库才能加载一些数据，但是一旦我更改标签当我点击我的登录按钮时，所选的第一个标签显示
一半或冻结

：

< pre class ="lang-cs prettyprint prettyprinted"style =""> private void btncon_Click （ 对象 发件人 ， EventArgs e ）
{
strLogin = tblogin 。 文字 。 修剪 （）;
pass = tbpwd 。 文字 ;
如果 （！ backgroundWorker1 。 IsBusy ）
backgroundWorker1 。 RunWorkerAsync （ ）;
}

和

 
   private     void   backgroundWorker1_DoWork  （  对象 发件人 ，    DoWorkEventArgs   e  ） < span class ="pln"> 
   {  
   string   []  用户  =   cm  。  login  （ < span class ="pln"> strLogin  ，  pass  ）;   
   int   dataload   =     0  ;   
  如果 （ 用户  [  0  ]    ！=     null  ）  
   {  
成功  =     true  ;   
  }   
   else   
   {  
成功  =     false  ;   
  }   
  }   
 

所以当 backgroundworker1 已经完成，我打电话给 backgroundWorker2

   private     void   backgroundWorker1_RunWorkerCompleted  （  object   sender  ，    RunWorkerCompletedEventArgs   e  ）  
   {  
  如果   （ 成功 ）  
   {  
 backgroundWorker2  。  RunWorkerAsync  < span class ="pun">（）;   
  }   
   else   
   {  
  此 。 显示 （）;   
  }   
  }   

和

   main   Principale  ;     //主要表格  
   private     void   backgroundWorker2_DoWork  （  object   sender  ，    DoWorkEve ntArgs   e  ）  
   {  
   Principale     =     new   main  （）;   
  }   
 
   private     void   backgroundWorker2_RunWorkerCompleted  （  object   sender  ，    RunWorkerCompletedEventArgs   e  ）  
   { < span class ="pln"> 
   this  。 隐藏 （）;     / / hide login winform   
   Principale  。 显示 （）;     // show mainform   
  }   

解决方案

>> ...一旦我更改标签页，所选的第一个标签显示为一半或冻结

<我想这个问题可能是由耗时的操作引起的，例如从数据库加载数据。

要解决它，你可以尝试添加一个新的后台工作来执行操作加载数据：

 bool changed = false; 
 
 private void tabControl1_Selected（object sender，TabControlEventArgs e）
 {
 changed = true; 
 if（！backgroundWorker1.IsBusy）
 {
 if（changed）
 {
 backgroundWorker1.RunWorkerAsync（）; 
} 
} 
} 
 
 private void backgroundWorker1_DoWork（对象发送者，DoWorkEventArgs e）
 {
 //模拟耗时的操作从DB 
中加载数据int sum = 0; 
 for（int i = 0; i< int.MaxValue; i ++）
 {
 sum + = i; 
} 
 textBox1.Text = sum.ToString（）; 
 //模拟从DB上加载数据的耗时操作
 
 changed = false; 
} 

问候，

Stanly

Hi ,

i have a winform called login that asks username and password , checks the information with a database(online) and then displays the main winform , but to avoid that the application freezes , i used two backgroundworker.

On my main winform I have several tabs that need the connection to the database to load some data but as soon as I change tab the first tab selected appears half or freeze
when I click on my login button :

 private  void btncon_Click(object sender, EventArgs e)
 {
    strLogin = tblogin.Text.Trim();
    pass = tbpwd.Text;
    if (!backgroundWorker1.IsBusy)
        backgroundWorker1.RunWorkerAsync();
 }

and

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            string[] user = cm.login(strLogin, pass);
            int dataload = 0;
            if(user[0] != null)
            {
               success = true;
            }
            else
            {
                success = false;
            }
        }

so when backgroundworker1 has finished , i call backgroundWorker2

private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (success)
            {
                backgroundWorker2.RunWorkerAsync();
            }
            else
            {
                this.Show();
            }
        }

and for

main Principale; //main form
private void backgroundWorker2_DoWork(object sender, DoWorkEventArgs e)
{
  Principale = new main();
}

    private void backgroundWorker2_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
      this.Hide(); //hide login winform
      Principale.Show(); //show mainform
    }

解决方案

Hi,

>>… as soon as I change tab the first tab selected appears half or freeze

I guess this problem might be caused by time-consuming operations, such as loading data from database.

To solve it, you can try to add a new backgroundworker to perform the operation of loading data:

    bool changed = false;

    private void tabControl1_Selected(object sender, TabControlEventArgs e)
    {
        changed = true;
        if (!backgroundWorker1.IsBusy)
        {
            if (changed)
            {
                backgroundWorker1.RunWorkerAsync();
            }
        }
    }

    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        // time-consuming operations to simulate loading data from DB
        int sum = 0;
        for (int i = 0; i < int.MaxValue; i++)
        {
            sum += i;
        }
        textBox1.Text = sum.ToString();
        // time-consuming operations to simulate loading data from DB

        changed = false;
    }

Regards,

Stanly

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