动态用户控件的点击事件 [英] Dynamic-usercontrol click event

问题描述

用户控件：

 私人字符串的lastName; 
公共字符串姓氏
 {
得到{lastName的; } 
组
 {
 lastName的=价值; 
 lastNameTextBox.Text =价值; 
} 
} 
  

形式：

 使用（SqlConnection的myDatabaseConnection =新的SqlConnection（myConnectionString.ConnectionString））
 {
 myDatabaseConnection.Open（）;使用
（的SqlCommand的SqlCommand =新的SqlCommand（选择LasatName从雇员，myDatabaseConnection））
 {
 INT I = 0; 
 SqlDataReader的DR1 = SqlCommand.ExecuteReader（）; 
，而（DR1.Read（））
 {
 I ++; 
 UserControl2用户控件=新UserControl2（）; 
 usercontrol.Tag = I; 
 usercontrol.LastName =（字符串）DR1 [姓氏]; 
 usercontrol.Click + =新的EventHandler（usercontrol_Click）; 
 flowLayoutPanel1.Controls.Add（用户控件）; 
} 
} 
} 
  

的形式加载从记录数据库并显示在动态创建的每个用户控件文本框，每个姓氏。 ？
如何显示产生额外的信息，如窗体的文本地址时，一个动态用户控件点击

尝试：

 私人无效usercontrol_Click（对象发件人，EventArgs五）
 {$ b $使用（SqlConnection的myDatabaseConnection =新的SqlConnection（myConnectionString.ConnectionString））
 b {
 myDatabaseConnection.Open（）; 
使用（的SqlCommand的MySqlCommand =新的SqlCommand（，myDatabaseConnection），从员工那里名字= @LastName选择地址）
 
 {
 UserControl2用户控件=新UserControl2（）; 
 mySqlCommand.Parameters.AddWithValue（@姓，usercontrol.LastName; 
 SqlDataReader的= SQLReader的mySqlCommand.ExecuteReader（）; 
 
如果（sqlreader.Read（））
 {
 textBox1.Text =（字符串）SQLReader的[地址]; 
} 
 
} 
} 
} 
  

解决方案

首先，在你的第一个代码片段中，执行从选择ID .. ，而是希望找到场姓氏的读者 - 行不通的。

其次如果你知道你需要从<$ C的更多信息。 $ C>员工表，我建议你把它存储在同一用户控件，你把姓。执行从...选择*，另一个字段和属性添加到 UserControl2 ，并在读循环：

  usercontrol.Address =（字符串）DR1 [地址]; 
  





第三。在你的第二个代码段，用

  UserControl2用户控件=（UserControl2）发送; 
  

而不是

  UserControl2用户控件=新UserControl2（）; 
  

由于新创建的用户控件将不会有任何姓分配

然后：

 私人无效usercontrol_Click（对象发件人，EventArgs五）
 {
 UserControl2用户控件=（UserControl2）发送; 
 textBox1.Text = usercontrol.Address; 
} 
  

UserControl:

private string lastName;
public string LastName
{
get { return lastName; }
set
{
    lastName = value;
    lastNameTextBox.Text = value;
}
}

Form:

using (SqlConnection myDatabaseConnection = new SqlConnection(myConnectionString.ConnectionString))
        {
            myDatabaseConnection.Open();
            using (SqlCommand SqlCommand = new SqlCommand("Select LasatName from Employee", myDatabaseConnection))
            {
                int i = 0;
                SqlDataReader DR1 = SqlCommand.ExecuteReader();
                while (DR1.Read())
                {
                    i++;
                    UserControl2 usercontrol = new UserControl2();
                    usercontrol.Tag = i;
                    usercontrol.LastName = (string)DR1["LastName"];
                    usercontrol.Click += new EventHandler(usercontrol_Click); 
                    flowLayoutPanel1.Controls.Add(usercontrol);
                }
            }
        }

The form loads the records from database and display each LastName in each usercontrols' textbox that created dynamically. How to show additonal information such as address in form's textbox when a dynamic-usercontrol is click?

Attempt:

    private void usercontrol_Click(object sender, EventArgs e)
    {
        using (SqlConnection myDatabaseConnection = new SqlConnection(myConnectionString.ConnectionString))
        {
            myDatabaseConnection.Open();
            using (SqlCommand mySqlCommand = new SqlCommand("Select Address from Employee where LastName = @LastName ", myDatabaseConnection))

            {
                UserControl2 usercontrol = new UserControl2();
                mySqlCommand.Parameters.AddWithValue("@LastName", usercontrol.LastName;
                SqlDataReader sqlreader = mySqlCommand.ExecuteReader();

                if (sqlreader.Read())
                {
                    textBox1.Text = (string)sqlreader["Address"];
                }

            }
        }
    }

解决方案

First. In your first code fragment, you execute "Select ID from ...", but expect to find field "LastName" in the reader - not going to work.

Second. If you know that you will need more information from Employee table, I suggest that you store it in the same UserControl where you put the LastName. Execute "Select * from ...", add another field and property to UserControl2 and assign it in the Read loop:

usercontrol.Address = (string)DR1["Address"];

Third. In your second code fragment, use

UserControl2 usercontrol = (UserControl2)sender;

instead of

UserControl2 usercontrol = new UserControl2();

because newly created user control will not have any LastName assigned.

Then:

private void usercontrol_Click(object sender, EventArgs e)
{
    UserControl2 usercontrol = (UserControl2)sender;
    textBox1.Text = usercontrol.Address;
}

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