删除查询不起作用 [英] delete query not working

问题描述

如何在提交按钮点击时删除gridview数据



我的网页上有gridview和一个按钮。



当页面加载时，数据显示在gridview上。



因此，当我点击提交按钮时，我想从表中删除完整数据。

因此无法在gridview中显示。



这是我的代码

 SqlConnection conDelete = new SqlConnection（_connString）; 
 SqlCommand cmdDelete = new SqlCommand（）; 
 cmdDelete.Connection = conDelete; 
 cmdDelete.CommandText =从学生中删除; 
使用（cmdDelete）
 {
 conDelete.Open（）; 
 
 cmdDelete.ExecuteNonQuery（）; 
 conDelete.Close（）; 
} 

这个不起作用请帮忙。





谢谢

解决方案

您需要为 sqlcommand [ ^ ]，如下所示：

 SqlConnection conDelete =  new  SqlConnection（_connString）; 
 conDelete.Open（）; 
 SqlCommand cmdDelete =  new  SqlCommand（  DELETE来自学生WHERE StudentId = 1，conDelete）; 
  int  retVal = cmdDelete.ExecuteNonQuery（）; 
  //   retval存储受影响的受访者的价值 

请记住，您需要将记录范围定义为 DELETE（ T-SQL） [ ^ ]，但如果要删除所有数据，则不需要WHERE语句：

  DELETE  
  FROM 学生

以上查询与 TRUNCATE TABLE（T-SQL） [ ^ ]。

使用此： -

  TRUNCATE   TABLE 学生

祝你好运

试试这个： -

  Dim  con  As  新 SqlConnection 
  Dim  cmd 作为 新 SqlCommand 
 尝试 
 con.ConnectionString =   Data Source = atisource; Initial Catalog = BillingSys; Persist Security Info = True; User ID = sa; Password = 12345678 
 con.Open（）
 cmd.Connection = con 
 cmd.CommandText =   DELETE FROM table_name 
 cmd.ExecuteNonQuery（） 
 
  Catch  ex  As 例外
 MessageBox.Show（  deletin时出错g记在桌子上......& ex.Message， 删除记录）
 最后 
 con.Close（）
 结束 尝试 

how to delete the gridview data when submit button click

I have gridview and a button on my webpage.

when pageloads, the data displays on gridview.

so when i clicks the submit button i want to delete the complete data from table.
so it cannot be displayed in gridview.

this is my code

SqlConnection conDelete = new SqlConnection(_connString);
         SqlCommand cmdDelete = new SqlCommand();
         cmdDelete.Connection = conDelete;
        cmdDelete.CommandText = "Delete from students";
        using (cmdDelete)
        {
            conDelete.Open();

            cmdDelete.ExecuteNonQuery();
            conDelete.Close();
        }

this is not working please help.


thanks

解决方案

You need to define connection for sqlcommand[^], like this:

SqlConnection conDelete = new SqlConnection(_connString);
conDelete.Open();
SqlCommand cmdDelete = new SqlCommand("DELETE FROM Students WHERE StudentId=1", conDelete);
int retVal = cmdDelete.ExecuteNonQuery();
//retval stores value for recoreds affected

Remember, you need to define records range to DELETE (T-SQL)[^], but if you want to delete all data, WHERE statement is not needed:

DELETE 
FROM Students

Above query differs from TRUNCATE TABLE (T-SQL)[^].

Use this :-

TRUNCATE TABLE students

Good luck

try for this:-

Dim con As New SqlConnection
Dim cmd As New SqlCommand
Try
con.ConnectionString = "Data Source=atisource;Initial Catalog=BillingSys;Persist Security Info=True;User ID=sa;Password=12345678"
con.Open()
cmd.Connection = con
cmd.CommandText = "DELETE FROM table_name"
cmd.ExecuteNonQuery()

Catch ex As Exception
MessageBox.Show("Error while deleting record on table..." & ex.Message, "Delete Records")
Finally
con.Close()
End Try

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