GridView selected record update[Answered] RSS

• • Reply
  asante_za

  Member

  17 Points

  146 Posts

  GridView selected record update

  Dec 16, 2016 04:28 PM|asante_za|LINK

  Trying to update GridView selected record. Almost there but getting the error below. Full code attached.

  Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
  Line 35:int id = Convert.ToInt32(GridView1.SelectedRow.Cells[0].Text.ToString());

  Please help.

  protected void Button1_Click(object sender, EventArgs e)
          {
              string connectionString = ConfigurationManager.ConnectionStrings["TrainingWebConnectionString"].ConnectionString;
              string checkOleDb = "";
              using (OleDbConnection myconnection = new OleDbConnection(connectionString))
              {
                  using (OleDbCommand myCommand = new OleDbCommand(checkOleDb, myconnection))
                  {
  
                      int id = Convert.ToInt32(GridView1.SelectedRow.Cells[0].Text.ToString());
                     
                      myCommand.CommandText = "UPDATE [TasksProject] SET [AsAtDate] = @DateTime WHERE [ID] = @id";
                      
  
                      myCommand.Parameters.AddWithValue("@DateTime", DateTime.Now.ToString());
                      
                      myconnection.Open();
                      myCommand.ExecuteNonQuery();
                  }
              }
          }
      }
  }

• • Reply
  codemovement...

  Contributor

  2340 Points

  807 Posts

  Re: GridView selected record update

  Dec 16, 2016 04:43 PM|codemovement.pk|LINK

  Avoid using ToString() because text is already string 

  use this

   int id = Convert.ToInt32(GridView1.SelectedRow.Cells[0].Text);

  instead of this

   int id = Convert.ToInt32(GridView1.SelectedRow.Cells[0].Text.ToString());

  If my solution works for you, please mark it as answer! It will help others.
  Get more information: http://codemovement.pk
  
  Thanks,
• • Reply
  asante_za

  Member

  17 Points

  146 Posts

  Re: GridView selected record update

  Dec 16, 2016 04:51 PM|asante_za|LINK

  Thanks, but still getting the same error message:

  Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
  
  

• • Reply
  codemovement...

  Contributor

  2340 Points

  807 Posts

  Re: GridView selected record update

  Dec 16, 2016 05:05 PM|codemovement.pk|LINK

  Actually i just noticed that you are doing the whole thing in wrong event method you have to do this OnSelectedIndexChanged of the GridView like this.

    void GridView1_SelectedIndexChanged(Object sender, EventArgs e)
    {
  	   string connectionString = ConfigurationManager.ConnectionStrings["TrainingWebConnectionString"].ConnectionString;
  		string checkOleDb = "";
  		using (OleDbConnection myconnection = new OleDbConnection(connectionString))
  		{
  			using (OleDbCommand myCommand = new OleDbCommand(checkOleDb, myconnection))
  			{
  
  				int id = Convert.ToInt32(GridView1.SelectedRow.Cells[0].Text);
  			   
  				myCommand.CommandText = "UPDATE [TasksProject] SET [AsAtDate] = @DateTime WHERE [ID] = @id";
  				
  
  				myCommand.Parameters.AddWithValue("@DateTime", DateTime.Now.ToString());
  				
  				myconnection.Open();
  				myCommand.ExecuteNonQuery();
  			}
  		}
    }

  If my solution works for you, please mark it as answer! It will help others.
  Get more information: http://codemovement.pk
  
  Thanks,
• • Reply
  asante_za

  Member

  17 Points

  146 Posts

  Re: GridView selected record update

  Dec 16, 2016 09:50 PM|asante_za|LINK

  No error message, but AsAtDate not getting updated. Could you please spot what is missing!

  Code attached.

   protected void Button1_Click(object sender, EventArgs e)
          {
              foreach (GridViewRow row in GridView1.Rows)
              {
                  int id = Convert.ToInt32(GridView1.DataKeys[row.RowIndex].Value);
  
              string connectionString = ConfigurationManager.ConnectionStrings["TrainingWebConnectionString"].ConnectionString;
              string checkOleDb = "";
              using (OleDbConnection myconnection = new OleDbConnection(connectionString))
              {
                  using (OleDbCommand myCommand = new OleDbCommand(checkOleDb, myconnection))
                  {
                                  
                          myCommand.CommandText = "UPDATE [TasksProject] SET [AsAtDate] = @DateTime WHERE [ID] = @id";
  
                         myCommand.Parameters.AddWithValue("@DateTime", DateTime.Now.ToString());
                         myCommand.Parameters.AddWithValue("@id", ID);
                          myconnection.Open();
                         myCommand.ExecuteNonQuery();
                        
                      }
                  }
              }
          }

• • Reply
  asante_za

  Member

  17 Points

  146 Posts

  Re: GridView selected record update

  Dec 17, 2016 05:38 AM|asante_za|LINK

  I have got it! at last!

  Find full code attached.

  James

  using System;
  using System.Data;
  using System.Configuration;
  using System.Collections;
  using System.Web.Security;
  using System.Web.UI;
  using System.Web.UI.WebControls;
  using System.Web.UI.WebControls.WebParts;
  using System.Web.UI.HtmlControls;
  using System.Data.OleDb;
  using System.Collections.Generic;
  using System.Linq;
  using System.Web;
  
  
  
  namespace Trainingbundle
  {
      public partial class TaskDevList2 : System.Web.UI.Page
      {
          protected void Page_Load(object sender, EventArgs e)
          {
              
          }
  
          protected void Button1_Click(object sender, EventArgs e)
          {
              foreach (GridViewRow row in GridView1.Rows)
              {
                  int id = Convert.ToInt32(GridView1.DataKeys[row.RowIndex].Value);
  
              string connectionString = ConfigurationManager.ConnectionStrings["TrainingWebConnectionString"].ConnectionString;
              string checkOleDb = "";
              using (OleDbConnection myconnection = new OleDbConnection(connectionString))
              {
                  using (OleDbCommand myCommand = new OleDbCommand(checkOleDb, myconnection))
                  {
                                  
                          myCommand.CommandText = "UPDATE [TasksProject] SET [AsAtDate] = @DateTime WHERE [id] = @id";
  
                         myCommand.Parameters.AddWithValue("@DateTime", DateTime.Now.ToString());
                         myCommand.Parameters.AddWithValue("@id", id);
                          myconnection.Open();
                         myCommand.ExecuteNonQuery();
                        
                      }
                  }
              }
          }