想在我的数据库和数据网格视图中进行更新 [英] want to make update in my database and datagrid view

问题描述

美好的一天，



我写了一个代码来更新DataGridView中的单元格，但是在运行异常时发生了



索引超出范围。必须是非负数且小于集合的大小。

参数名称：index



我不知道是什么问题，我的代码有什么问题吗？



注意：我创建了一个DBclass包含所有sqlcommands和i cast当我需要写quires时。





这是我的代码：

  private   void  btn_update_Click（ object  sender，EventArgs e）
 {
 
 DBClass db = DBClass.GetInstance（）; 
  for （ int  i =  0 ; i< = dgv_contents.RowCount; i ++）
 {
  string  str =  @   
 UPDATE [Picture_upload]。[dbo]。[Contents] 
 SET [cont_name] =' + dgv_contents.SelectedRows [ i] .Cells [ 0 ]。值+ 
  '，[cont_type] =' + dgv_contents.Rows [i] .Cells [ 1 ]。值+ 
  '，[Description] =' + dgv_contents.Rows [i] .Cells [ 2 ]。值+ 
  '，[price] = + dgv_contents.Rows [i] .Cells [ 3 ]。值+  ; 
 
 db.ExecuteNonQuery（str，CommandType.Text）; 
} 

解决方案

DataGridView的RowCount属性为您提供个行。



但每行的索引从0（零）开始。



因此在你的for循环中

  for （ int  i = < = 你在DGV的实际行结束时运行。
 
 
 
将其更改为

试试这个代码..

  private   void  btn_update_Click（ object  sender，EventArgs e）
 {
 
 DBClass db = DBClass.GetInstance （）; 
 
  foreach （DataGridViewRow row  in   dgv_contents.SelectedRows ）
 {
  string  str =  @  
 UPDATE [Picture_upload]。[dbo]。[Contents] 
 SET [cont_name] =' + row.Cells [ 0 ]。值+ 
  '，[cont_type] =' + row.Cells [ 1 ]。值+ 
  '，[Description] =' + row.Cells [ 2 ]。值+ 
  '，[price] = + row.Cells [ 3 ] .Value +  ; 
 
 db.ExecuteNonQuery（str，CommandType.Text）; 
} 
 
 
} 
 

这对SQL注入攻击是开放的，即使您的表单不允许这些单元格上的文本框。你应该通过存储过程来做到这一点。你不应该在你的表示层写这么多的DB代码。

Good day all,

I wrote a code for updating cells in DataGridView , but while running an Exception occurred

"Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index"

I don't know what's the problem ,Is there anything wrong in my code ?

Note : i made a DBclass contains all sqlcommands and i cast it when i need to write quires.


Here's my Code:

private void btn_update_Click(object sender, EventArgs e)
       {

           DBClass db=DBClass.GetInstance();
           for(int i=0;i<=dgv_contents.RowCount;i++)
           {
           string str = @"
           UPDATE [Picture_upload].[dbo].[Contents]
  SET [cont_name] = '"+dgv_contents.SelectedRows[i].Cells[0].Value+
                      "',[cont_type] ='"+dgv_contents.Rows[i].Cells[1].Value+
                      "',[Description] ='"+dgv_contents.Rows[i].Cells[2].Value+
                      "',[price] = "+dgv_contents.Rows[i].Cells[3].Value+"";

           db.ExecuteNonQuery(str,CommandType.Text);
           }

解决方案

The RowCount property of a DataGridView gives you the number of rows.

But the index of each row starts at 0 (zero).

Thus in your for loop

for(int i=0;i<=dgv_contents.RowCount;i++)

by using <= you are running off the end of actual rows in the DGV.

Change it to just be

Try this code..

private void btn_update_Click(object sender, EventArgs e)
       {

           DBClass db = DBClass.GetInstance();

           foreach (DataGridViewRow row in dgv_contents.SelectedRows)
           {
               string str = @"
          UPDATE [Picture_upload].[dbo].[Contents]
 SET [cont_name] = '" + row.Cells[0].Value +
                           "',[cont_type] ='" + row.Cells[1].Value +
                           "',[Description] ='" + row.Cells[2].Value +
                           "',[price] = " + row.Cells[3].Value + "";

               db.ExecuteNonQuery(str, CommandType.Text);
           }


       }

This is open to SQL injection attacks, even if your form doesn't allow text boxes on these cells. You should do this via a stored proc. You should NEVER write this much DB code in your presentation layer.

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