Question

Tengo un problema con el evento RowUpdating de un GridView de ASP.Net. Cuando quiero saber el valor de una celda y por alguna razon, no me los trae. Me dan nulos.

Les dejo el codigo para que puedan ver.

Categories.aspx

<%@ Page Title="Category Administration" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="Categories.aspx.cs" Inherits="Example.Client.GUI.forum.Administration.Categories" Debug="true" Trace="true" TraceMode="SortByTime" %>

<asp:Content ID="cntHead" ContentPlaceHolderID="HeadContent" runat="server">
</asp:Content>
<asp:Content ID="cntBody" ContentPlaceHolderID="MainContent" runat="server">
    <%-- hidden --%>
    <asp:HiddenField ID="hidAlgo" runat="server" />
    <%-- error --%>
    <asp:Panel ID="pnlError" CssClass="alert alert-danger" role="alert" runat="server" Visible="false">
        <asp:Literal ID="litError" runat="server" />
    </asp:Panel>
    <%-- grid --%>
    <asp:Panel CssClass="panel panel-default" runat="server">
        <asp:Panel CssClass="panel-heading" runat="server">
            <asp:Literal Text="Categories" runat="server" />
        </asp:Panel>
        <asp:GridView ID="gvCategories" runat="server" AutoGenerateColumns="False" CssClass="table table-hover" EnableTheming="False" GridLines="None" OnRowCancelingEdit="gvCategories_RowCancelingEdit" OnRowEditing="gvCategories_RowEditing" OnRowUpdating="gvCategories_RowUpdating" OnRowDeleting="gvCategories_RowDeleting" AllowPaging="True" AllowSorting="True" DataKeyNames="category_id">
            <Columns>
                <asp:BoundField DataField="category_id" HeaderText="Identifier" ReadOnly="True" />
                <asp:BoundField DataField="category_name" HeaderText="Name" />
                <asp:BoundField DataField="date_added" HeaderText="Date added" ReadOnly="True" />
                <asp:CommandField ShowEditButton="True" ShowDeleteButton="True" />
            </Columns>
        </asp:GridView>
    </asp:Panel>
</asp:Content>
<asp:Content ID="cntScripts" ContentPlaceHolderID="ScriptSection" runat="server">
</asp:Content>

Categories.aspx.cs

using presenter;
using System;
using System.Data;
using System.Web.UI;
using System.Web.UI.WebControls;
using view;

namespace Example.Client.GUI.forum.Administration
{
    public partial class Categories : Page, ICategoriesView
    {
        protected readonly CategoriesPresenter _presenter;

        public Categories()
        {
            _presenter = new CategoriesPresenter(this);
        }

        public void FillCategoriesGrid(DataSet dataset)
        {
            gvCategories.DataSource = dataset;
            gvCategories.DataBind();
        }

        public void ShowError(Exception ex)
        {
            pnlError.Visible = true;
            litError.Text = ex.Message;
        }

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                _presenter.LoadCategories();
            }            
        }

        protected void gvCategories_RowEditing(object sender, GridViewEditEventArgs e)
        {
            gvCategories.EditIndex = e.NewEditIndex;
            _presenter.LoadCategories();
        }

        protected void gvCategories_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
        {
            gvCategories.EditIndex = -1;
            _presenter.LoadCategories();
        }

        protected void gvCategories_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            string id = gvCategories.DataKeys[e.RowIndex].Value.ToString();
            string categoryName = gvCategories.Rows[e.RowIndex].Cells[1].Text;
            string dateadd = gvCategories.Rows[e.RowIndex].Cells[2].Text;

            _presenter.UpdateCategory(id, categoryName, dateadd);
            _presenter.LoadCategories();
        }

        protected void gvCategories_RowDeleting(object sender, GridViewDeleteEventArgs e)
        {
            string id = gvCategories.DataKeys[e.RowIndex].Value.ToString();

            _presenter.DeleteCategory(id);
            _presenter.LoadCategories();
        }
    }
}

CategoriesPresenter.cs

using mvp;
using System;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using view;

namespace presenter
{
    public class CategoriesPresenter : Presenter<ICategoriesView>
    {
        protected readonly SqlConnection _conn;

        public CategoriesPresenter(ICategoriesView view)
            : base(view)
        {
            _conn = new SqlConnection(ConfigurationManager.ConnectionStrings["SqlConnection"].ConnectionString);
        }

        public void LoadCategories()
        {
            try
            {
                _conn.Open();
                var command = _conn.CreateCommand();
                command.CommandText = "SELECT category_id, category_name, date_added FROM forum_categories;";
                var adapter = new SqlDataAdapter(command);
                var dataset = new DataSet();
                adapter.Fill(dataset);
                View.FillCategoriesGrid(dataset);
            }
            catch (Exception ex)
            {
                View.ShowError(ex);
            }
            finally
            {
                if (_conn != null && _conn.State == ConnectionState.Open)
                {
                    _conn.Close();
                }
            }
        }

        public void UpdateCategory(string id, string categoryName, string dateadd)
        {
            try
            {
                var command = _conn.CreateCommand();                
                command.CommandText = "UPDATE forum_categories SET category_name = @categoryName, date_added = @dateadd WHERE category_id = @id;";
                command.CommandType = CommandType.Text;
                command.Parameters.Add("@id", SqlDbType.Int).Value = id;
                command.Parameters.Add("@categoryName", SqlDbType.VarChar, 100).Value = categoryName;
                command.Parameters.Add("@dateadd", SqlDbType.DateTime).Value = Convert.ToDateTime(dateadd);
                _conn.Open();
                command.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                View.ShowError(ex);
            }
            finally
            {
                if (_conn != null && _conn.State == ConnectionState.Open)
                {
                    _conn.Close();
                }
            }
        }

        public void DeleteCategory(string id)
        {
            try
            {
                var command = _conn.CreateCommand();
                command.CommandText = "DELETE FROM forum_categories WHERE category_id = @id;";
                command.CommandType = CommandType.Text;
                command.Parameters.Add("@id", SqlDbType.Int).Value = id;
                _conn.Open();
                command.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                View.ShowError(ex);
            }
            finally
            {
                if (_conn != null && _conn.State == ConnectionState.Open)
                {
                    _conn.Close();
                }
            }
        }
    }
}

Si necesitan mas informacion, no duden en comentarmelo que lo anexó a la pregunta.

Answer 1

Solucionado.

Encare el problema de manera incorrecta. Debí haber usado los argumentos de evento para obtener los nuevos valores.

Quedaria una cosa asi:

protected void gvCategories_RowUpdating(object sender, GridViewUpdateEventArgs e)
        {
            string id = gvCategories.DataKeys[e.RowIndex].Value.ToString();
            string categoryName = e.OldValues["category_name"] != e.NewValues["category_name"]
                ? e.NewValues["category_name"].ToString()
                : e.OldValues["category_name"].ToString();
            string dateadd = gvCategories.Rows[e.RowIndex].Cells[2].Text;

            _presenter.UpdateCategory(id, categoryName, dateadd);
            _presenter.LoadCategories();
        }