如何从表中删除 [英] How Do I Delete From A Table

问题描述

嘿，我想删除一个选定的工作人员（显示在列表框中）/我的代码

  private   void  button2_Click（ object  sender，EventArgs e）
 {
 SqlConnection con =  new  SqlConnection（ 数据源= JAMES-PC\\SQLEXPRESS;初始目录=员工;集成安全性=真）; 
 con.Open（）; 
 
  string  sql =  @  DELETE FROM staff1其中Id = @ name;; 
 
 SqlCommand cmd =  new  SqlCommand（sql，con）; 
 cmd.Parameters.AddWithValue（  @ name， 1 ）; 
 
 cmd.ExecuteNonQuery（）; 
 con.Close（）; 
} 

但是当我运行程序时，我点击按钮（删除）但是没有运气，没有删除它

任何帮助将不胜感激

列表框中显示的表格是（名称）

解决方案

  private   void  button2_Click（ object  sender，EventArgs e）
 {
 SqlConnection con =  new  SqlConnection（ 数据源= JAMES-PC\\SQLEXPRESS;初始目录=员工;集成安全性=真）; 
 con.Open（）; 
 
  string  sql =  @  DELETE FROM staff1其中Id = @ name;; 
 
 SqlCommand cmd =  new  SqlCommand（sql，con）; 
 cmd.Parameters.AddWithValue（  @ name， listBox1.SelectedValue。的ToString（）的）; 
 
 cmd.ExecuteNonQuery（）; 
 con.Close（）; 
} 

看看参数id是否为varchar，它是这样的：

DELETE FROM staff1其中Id ='staff1';

转到Web Config并粘贴此

 <   connectionStrings  >  
 <   add     name   =  constring    connectionString   = 数据source = JAMES-PC\\SQLEXPRESS; initial catalog = staff; persist security info = true; integrated security = true   的providerName  < span class =code-keyword> =  System.Data.SqlClient  /  >  
 <   / connectionStrings  >  

和chane代码如下

 private void button2_Click（object sender，EventArgs e）
 {
 SqlConnection con = new SqlConnection（ConfigurationManager.ConnectionStrings [constring ] .ConnectionString）; 
 con.Open（）; 
 
 string sql = @DELETE FROM staff1 where name = @ name;; 
 
 SqlCommand cmd = new SqlCommand（DELETE FROM staff1 where name = @ name，con）; 
 cmd.Parameters.AddWithValue（@ name，1）;或//cmd.Parameters.AddWithValue(\"@name，listBox1.SelectedItem.ToString（））; 
 
 cmd.ExecuteNonQuery（）; 
 con.Close（）; 
} 

始终带id进行删除。谢谢： - ）

hey , i want to delete a selected "staff member" (displayed in listbox) / my code

private void button2_Click(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection("Data Source=JAMES-PC\\SQLEXPRESS;Initial Catalog=staff;Integrated Security=True");
            con.Open();

            string sql = @"DELETE FROM staff1 where Id=@name;";

            SqlCommand cmd = new SqlCommand(sql, con);
            cmd.Parameters.AddWithValue("@name", 1);

            cmd.ExecuteNonQuery();
            con.Close();
        }

but when i run the program i click the button (remove) but no luck, doesnt delete it
any help would be appreciated
also the table displayed in the listbox is (name)

解决方案

private void button2_Click(object sender, EventArgs e)
{
            SqlConnection con = new SqlConnection("Data Source=JAMES-PC\\SQLEXPRESS;Initial Catalog=staff;Integrated Security=True");
            con.Open();
 
            string sql = @"DELETE FROM staff1 where Id=@name;";
 
            SqlCommand cmd = new SqlCommand(sql, con);
            cmd.Parameters.AddWithValue("@name", listBox1.SelectedValue.ToString());
 
            cmd.ExecuteNonQuery();
            con.Close();
}

see if the parameter id is varchar it is enclosed like this:
DELETE FROM staff1 where Id= 'staff1';

Go to Web Config and paste this

<connectionStrings>
    <add name="constring" connectionString="data source=JAMES-PC\\SQLEXPRESS; initial catalog=staff; persist security info= true; integrated security= true" providerName="System.Data.SqlClient"/>
  </connectionStrings>

and chane the code as follow

private void button2_Click(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constring"].ConnectionString);
            con.Open();
 
            string sql = @"DELETE FROM staff1 where name=@name;";
 
            SqlCommand cmd = new SqlCommand("DELETE FROM staff1 where name=@name", con);
            cmd.Parameters.AddWithValue("@name", 1); or  //cmd.Parameters.AddWithValue("@name", listBox1.SelectedItem.ToString());
 
            cmd.ExecuteNonQuery();
            con.Close();
        }

Always go with id for deletion.Thank You:-)

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