我的代码有什么错误? [英] Whats the error in my Code?

问题描述

尊敬的荣誉，

在我的Windows应用程序中，存储并检索图像...存储图像时没有问题..但是，当我从数据库中获取图像数据时，以下错误正在上升...

Dear Honors,

In my windows application am store and retrieve the images... There is no problem while store the image.. But When I fetch the image data from database the following error is rising...

System.ArgumentException: Parameter is not valid.

这是我的代码...

如果可能，请更改我的代码....

Here is my code...

If possible kindly alter my code....

private void cmbID_SelectedIndexChanged(object sender, EventArgs e)
       {
           try
           {
               Query = "Select Photo from tblTest where ID = '" + cmbID.Text + "'";
               SqlCmd = new SqlCommand(Query, SqlCon);

                 SqlDR = SqlCmd.ExecuteReader();
                 if (SqlDR.Read())
                 {

                     byte[] imageData = (byte[])SqlDR["Photo"];


                     Image newImage;

                     using (MemoryStream ms = new MemoryStream(imageData, 0, imageData.Length))
                     {
                         ms.Write(imageData, 0, imageData.Length);

                         //Set image variable value using memory stream.
                         newImage = Image.FromStream(ms, true);
                     }

                     //set picture
                     pictureBox1.Image = newImage;
                 }
                 SqlDR.Dispose();


           }
           catch (Exception ex)
           {
               MessageBox.Show(ex.ToString());
           }
       }

推荐答案

使用调试器，尝试缩小获取异常的行范围.

一个可能的原因是因为yuo在您的SQL语句中使用了文字.您应该使用 SqlParameter [

Using debugger, try to narrow down from what line you''re getting the exception.

One possible cause is because yuo have used literals in your SQL statement. You should use SqlParameter[^] in any case so your query would look like:

SqlCmd = new SqlCommand(Query, SqlCon);
Query = "Select Photo from tblTest where ID = @id";
SqlCmd.Parameters.AddWithValue("@id,"cmbID.Text);
SqlDR = SqlCmd.ExecuteReader();

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