Object reference not set to an instance of an object.

Question

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Hi
I have used the dataSource Manually(Connecting in Properties) as well as in coding ..
I am working on RadGrid CRUD operation,While connecting the database in code it shows object refernce is not set.

What I have tried:

C#

<pre>using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Text;
using System.Web.UI.WebControls;
using System.Data.Sql;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using Telerik.Web.UI;


namespace Telerik08._03
{
    public partial class Sample123 : System.Web.UI.Page
    {
        SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["sqlconnection"].ConnectionString);
        
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                bind();
            }
        }




        private static void ShowCheckedItems(Telerik.Web.UI.RadComboBox comboBox, Literal literal)
        {
            //var obj = new StringBuilder();
            //var collection = comboBox.CheckedItems;

            //if (collection.Count != 0)
            //{
            //    obj.Append("<h3>Checked Items:</h3><ul class=\"results\">");

            //    foreach (var item in collection)
            //        obj.Append("<Items>" + item.Text + "</Items>");

            //    obj.Append("</ul>");

            //    //    literal.Text = obj.ToString();
            //}
            //else
            //{
            //    literal.Text = "<p>No items selected</p>";
            //}
        }
        
        protected void RadComboBox1_SelectedIndexChanged(object sender, Telerik.Web.UI.RadComboBoxSelectedIndexChangedEventArgs e)
        {

        }
        
        protected void Button1_Click(object sender, EventArgs e)
        {
            //ShowCheckedItems(RadComboBox2, itemsClientSide);
        }
        protected void RadComboBox2_DataBound(object sender, EventArgs e)
        {

           
        }
        protected void RadComboBox2_ItemsRequested(object sender, RadComboBoxItemsRequestedEventArgs e)
        {

            //string sql = "SELECT * from gvdetails17 " ;

            //SqlDataSource1.SelectCommand = sql;
            //RadComboBox2.DataBind();
        }
        protected void RadComboBox2_ItemDataBound(object sender, RadComboBoxItemEventArgs e)
        {
            //e.Item.Value = ((DataRowView)e.Item.DataItem)["EmpId"].ToString()
            //    + ";" + ((((DataRowView)e.Item.DataItem)["EmpName"].ToString()))
            //    + ";" + (((DataRowView)e.Item.DataItem)["Dep"].ToString());
            //e.Item.Text = ((DataRowView)e.Item.DataItem)["Dep"].ToString();
            //e.Item.Text = ((DataRowView)e.Item.DataItem)["Dep"].ToString();
           
            
        }
        

         protected void RadGrid1_ItemUpdated(object source, Telerik.Web.UI.GridUpdatedEventArgs e)
        {

             


        }
         protected void bind()
         {
             cn.Open();
             SqlCommand cmd = new SqlCommand("Select * from gvdetails17", cn);
             SqlDataAdapter da = new SqlDataAdapter(cmd);
             DataSet ds = new DataSet();
             da.Fill(ds);
             cn.Close();
             if (ds.Tables[0].Rows.Count > 0)
             {
                 RadGrid1.DataSource = ds;
                 RadGrid1.DataBind();
             }
         }

         protected void RadGrid1_DeleteCommand(object source, Telerik.Web.UI.GridCommandEventArgs e)
         {
             
             GridDataItem item = (GridDataItem)e.Item;
             
             string EmployeeID = item.OwnerTableView.DataKeyValues[item.ItemIndex]["EmpID"].ToString();
             try
             {
                
                  cn.Open();
                  SqlCommand cmd = new SqlCommand("delete from gvdetails17 where EmpId=" + EmployeeID, cn);
            int result = cmd.ExecuteNonQuery();
            cn.Close();
                 

             }
             catch (Exception ex)
             {
                 RadGrid1.Controls.Add(new LiteralControl("Unable to delete Employee. Reason: " + ex.Message));
                 e.Canceled = true;
             }


         }  
        public RadComboBoxItem item { get; set; }

        public RadComboBoxItem EmpName { get; set; }

        protected void RadComboBox2_SelectedIndexChanged(object sender, RadComboBoxSelectedIndexChangedEventArgs e)
        {

        }

My aspx page

ASP.NET

<pre><%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Sample123.aspx.cs" Inherits="Telerik08._03.Sample123" %>
<%@ Register TagPrefix="telerik" Namespace="Telerik.Web.UI" Assembly="Telerik.Web.UI" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
        <style>
            .col1,
.col2,
.col3 {
    margin: 0;
    padding: 0 5px 0 0;
    width: 30%;
    line-height: 14px;
    float: left;
}
        .multipleRowsColumns .rcbItem,
.multipleRowsColumns .rcbHovered {
    float: left;
    margin: 0 1px;
    min-height: 13px;
    overflow: hidden;
    padding: 2px 19px 2px 6px;
    width: 193px;
}
 .exampleRadComboBox.RadComboBoxDropDown .rcbHeader {
    padding: 5px 27px 4px 7px;
}
 
.results {
    display: block;
    margin-top: 20px;
}



        .RadDock a {
    color: #58954D;
}
        .alternateItemStyle
{
    background-color: #FFFFFF;
    color: #000000;
    font-size: 8pt;
}

 
.higherZIndex {
    z-index: 2;
}

.demo-container.wrapper {
    background-image: url(images/background.png);
    background-repeat: no-repeat;
    width: 260px;
    padding: 190px 30px 10px;
    margin: 0 auto;
    border: 0 none;
 
}
 
.demo-container > .RadInput,
.demo-container .RadPicker,
.button-wrapper .RadButton {
    width: 100%;
    margin-bottom: 10px;
}
 
html .rbCheckBox {
    vertical-align: middle;
}
 
.button-wrapper {
    padding: 25px 13px 0;
}
 
.background-material .rbCheckBox,
.background-material .RadLabel {
    margin-left: 13px;
    margin-right: -13px;
}
    </style>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
    <script src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.9/jquery-ui.js" type="text/javascript"></script>
    <link href="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.9/themes/start/jquery-ui.css"
        rel="stylesheet" type="text/css" />
    <script type="text/javascript">
<%--     $(function () {

            var grid = document.getElementById('<%= RadGrid1.ClientID%>');
            $('tr', grid).on('dblclick', function (obj, b) {

                $("#id").html($(".clsempid", $(this).closest("tr")).html());
               
                $("#dialog").dialog({
                    title: "View Details",
                    buttons: {
                        Ok: function () {
                            $(this).dialog('close');
                        }
                    },
                    modal: true
                });

            })
        });--%>
</script>
</head>
<body>
    <form id="form1" runat="server">
        <telerik:RadScriptManager runat="server" ID="RadScriptManager1" />
    <telerik:RadSkinManager ID="RadSkinManager1" runat="server" ShowChooser="true" />
    <telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
        <AjaxSettings>
            <telerik:AjaxSetting AjaxControlID="Button1">
                <UpdatedControls>
                    <telerik:AjaxUpdatedControl ControlID="Label1" />
                </UpdatedControls>
            </telerik:AjaxSetting>
        </AjaxSettings>
    </telerik:RadAjaxManager>

        <table style="margin-left:471px;margin-bottom:-27px">
            <tr>
                <td>
                    <telerik:RadComboBox RenderMode="Classic" ID="RadComboBox1" Text="Select" runat="server"
                        CheckBoxes="true" EnableCheckAllItemsCheckBox="true" MarkFirstMatch="true"  HighlightTemplatedItems="true"
                        AutoPostBack="true" ValueField="--Select--" OnSelectedIndexChanged="RadComboBox1_SelectedIndexChanged"
          > <%--HighlightTemplatedItems="true" OnClientItemsRequested="UpdateItemCountField"
            OnDataBound="RadComboBox1_DataBound" OnItemDataBound="RadComboBox1_ItemDataBound"
            OnItemsRequested="RadComboBox1_ItemsRequested" DropDownCssClass="exampleRadComboBox"> --%>
                        <Items>

                            <telerik:RadComboBoxItem Text="Dotnet" />
                            <telerik:RadComboBoxItem Text="Java" />
                            <telerik:RadComboBoxItem Text="Sales" />
                            <telerik:RadComboBoxItem Text="Hr" />
                            <telerik:RadComboBoxItem Text="Admin" />
                        </Items>
                    </telerik:RadComboBox>
                </td>
            </tr>
        </table>
        <telerik:RadComboBox RenderMode="Lightweight" runat="server" ID="RadComboBox2" style="margin-left:671px;margin-bottom:24px;width:250px"
             DataSourceID="SqlDataSource1" AutoPostBack="true" Text="Select" MarkFirstMatch="true" EnableLoadOnDemand="true" HighlightTemplatedItems="true"
             ValueField="--Select--"
            OnDataBound="RadComboBox2_DataBound" OnItemDataBound="RadComboBox2_ItemDataBound"
              OnSelectedIndexChanged="RadComboBox2_SelectedIndexChanged">
           <HeaderTemplate>
                <ul>
                    <li class="col1">Employee ID</li>
                    <li class="col2">Employee Name</li>
                    <li class="col3">Salary</li>
                    <li class="col3">Department</li>
                    <li class="col3">Age</li>
                </ul>
            </HeaderTemplate>
            <ItemTemplate>
                <table>
                    <tr>
                        <td style="width: 225px">
                            <%#DataBinder.Eval(Container.DataItem,"EmpId") %>

                        </td>
                        <td style="width: 225px">
                            <%#DataBinder.Eval(Container.DataItem,"EmpName") %>

                        </td>
                        <td style="width: 225px">
                            <%#DataBinder.Eval(Container.DataItem,"Sal") %>

                        </td>
                        <td style="width: 225px">
                            <%#DataBinder.Eval(Container.DataItem,"Dep") %>

                        </td>
                        <td style="width: 225px">
                            <%#DataBinder.Eval(Container.DataItem,"Age") %>

                        </td>
                    </tr>


                </table>
            </ItemTemplate>
            <FooterTemplate>
                A total of
                <asp:Literal runat="server" ID="RadComboItemsCount" />
                items
            </FooterTemplate>
        </telerik:RadComboBox>
        <telerik:RadButton RenderMode="Lightweight" runat="server" ID="Button1" Text="Select" OnClick="Button1_Click" ></telerik:RadButton>
        <asp:Label runat="server" ID="Label1" />

        <div style="margin-top:-46px;background-color:lightgreen;     border-collapse: collapse;
               background-color: lightgreen;">


            <telerik:RadGrid ID="RadGrid1"  ShowStatusBar="true"   margin-top="-46px" Height="500px" runat="server"
                ShowGroupPanel="True" GridLines="None"  
                AllowPaging="True" AllowAutomaticDeletes="True" AllowAutomaticInserts="True"
                AllowFilteringByColumn="True"  OnDeleteCommand="RadGrid1_DeleteCommand"
              
                AllowSorting="True" AutoGenerateDeleteColumn="true" 
                AutoGenerateEditColumn="True" CellSpacing="0" DataSourceID="SqlDataSource1" 
                Skin="Forest" AllowCustomPaging="True" AllowMultiRowEdit="True" AllowMultiRowSelection="True" PageSize="20" >
               


                <HeaderContextMenu>
                    <CollapseAnimation Type="OutQuint" Duration="200" />

                </HeaderContextMenu>
                <MasterTableView GroupLoadMode="Client" AutoGenerateColumns="False"  DataSourceID="SqlDataSource1">
                    <Columns>
                        
                        <telerik:GridBoundColumn DataField="EmpId" DataType="System.Int32" FilterControlAltText="Filter EmpId column" HeaderText="EmployeeId" SortExpression="EmpId" UniqueName="EmpId">
                        </telerik:GridBoundColumn>
                        <telerik:GridBoundColumn DataField="EmpName" FilterControlAltText="Filter EmpName column" HeaderText="EmployeeName" SortExpression="EmployeeName" UniqueName="EmpName">
                        </telerik:GridBoundColumn>
                        <telerik:GridBoundColumn DataField="Dep" FilterControlAltText="Filter Dep column" HeaderText="Department" SortExpression="Dep" UniqueName="Department">
                        </telerik:GridBoundColumn>
                        <telerik:GridBoundColumn DataField="Age" FilterControlAltText="Filter Age column" HeaderText="Age" SortExpression="Age" UniqueName="Age">
                        </telerik:GridBoundColumn>
                        <telerik:GridBoundColumn DataField="Sal" DataType="System.Int32" FilterControlAltText="Filter Sal column" HeaderText="Salary" SortExpression="Salary" UniqueName="Sal">
                        </telerik:GridBoundColumn>
                        
                    </Columns>
                   
                    <EditFormSettings>
                        <EditColumn FilterControlAltText="Filter EditCommandColumn column"></EditColumn>
                        

                    </EditFormSettings>
                    
                </MasterTableView>
                <%--<ClientSettings AllowDragToGroup="true" AllowColumnsReorder="True" ReorderColumnsOnClient="True">


                 <Scrolling AllowScroll="True" UseStaticHeaders="True" />


             </ClientSettings>--%>
                 
            
                <FilterMenu>

                    

                </FilterMenu>

            </telerik:RadGrid>
            <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:SST321ConnectionString %>" SelectCommand="SELECT EmpId,EmpName,Dep,Age,Sal FROM [gvdetails17]"></asp:SqlDataSource>
        <asp:Literal ID ="itemsClientSide" runat="server" />
        </div>
    </form>
</body>
</html>

Posted 9-Mar-17 23:22pm

Member 12605293

Updated 10-Mar-17 1:13am

Add a Solution

Comments

Graeme_Grant 10-Mar-17 5:23am

Developers sacrifice and contribute their time for free to help fellow developers resolve difficulties. It is important that you are crystal clear about what you are experiencing with plenty of information so that your time and theirs are not wasted. The clearer the question, the better chance that you will get a favorable response in a timely manner.

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Karthik_Mahalingam 10-Mar-17 5:31am

which line ?

Member 12605293 10-Mar-17 6:47am

Connection string line "SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["sqlconnection"].ConnectionString);"

Karthik_Mahalingam 10-Mar-17 6:52am

post the connectionstring section from config file.

Member 12605293 10-Mar-17 6:57am

Done posting sir

Karthik_Mahalingam 10-Mar-17 6:58am

web.config file

Member 12605293 10-Mar-17 7:00am

yes done

Karthik_Mahalingam 10-Mar-17 7:03am

i meant the config section
<connectionstrings>
<add name="xx" connectionString="yy" >

Member 12605293 10-Mar-17 7:09am

Here are the details sir

Web.config

<connectionstrings>
<add name="SST321ConnectionString" connectionString="Data Source=.\sqlexpress;Initial Catalog=SST321;User ID=sa;Password=sst123"
providerName="System.Data.SqlClient" />

Aspx page

<asp:SqlDataSource runat="server" ID="SqlDataSource1"
ConflictDetection="CompareAllValues"
ConnectionString="<%$ ConnectionStrings:SST321ConnectionString%>"
SelectCommand="SELECT [EmpId], [EmpName], [Dep], [Age], [Sal] FROM [gvdetails17]">

Cs page

SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["SqlDataSource1"].ConnectionString);

Note:Is there any issues when the connection string is declared both in aspx and cs page???

Karthik_Mahalingam 10-Mar-17 7:13am

have posted the answer, please check

Member 12605293 21-Mar-17 4:12am

Hi Karthik

Karthik_Mahalingam 21-Mar-17 4:46am

Hi

Member 12605293 21-Mar-17 4:50am

I have tried a differnt way in grid view ,like doing the GridBind using View and Insert/Update/Delete operations using Stored Procedure..But it is not working suo

Karthik_Mahalingam 21-Mar-17 4:51am

post a question.

Member 12605293 21-Mar-17 4:51am

ok.

Karthik_Mahalingam 21-Mar-17 4:53am

let me help if i am aware

Member 12605293 24-Mar-17 4:57am

Hi Karthik I have a doubt

Karthik_Mahalingam 24-Mar-17 4:59am

Yes sir

Member 12605293 24-Mar-17 5:15am

Karthik, I am working on a Grid which has the Below details

Id,Name,Category,Age,Salary and using it inside a gridview and doing CRUD operations... While editing a particular id I want to show the Category as a dropdown and edit the person's category..

1.I have a table for category with its Id and Category name
2.I have main table which I have mentioned above ie(Id,Name,Category,Age,Salary )

Normally the grid should not show the dropdown,only on editing a column the category column must show a dropdown...

What I Have Tried is

When I bind the category column for dropdown how can I link that with my main table???

Karthik_Mahalingam 24-Mar-17 5:19am

asp grid view or third party?

Member 12605293 24-Mar-17 5:24am

third party

Karthik_Mahalingam 24-Mar-17 5:29am

i dont have proper solution for 3rd party, you shall post in their site.

Member 12605293 24-Mar-17 5:32am

ok sir

Member 12605293 24-Mar-17 7:27am

Sir I got some solutions for that thanks :)

Member 12605293 24-Mar-17 7:31am

Sir I hv some doubt in sql

Karthik_Mahalingam 24-Mar-17 7:32am

yes sir

Member 12605293 24-Mar-17 7:37am

How to achieve the below tables and join them

ID Name Dept Sal Techids
1 Abc Mech 20000 1,2,3

Techid Techname
1 Abc
2 def
3 ghi

Member 12605293 24-Mar-17 7:38am

Give me sample query Sir

Karthik_Mahalingam 24-Mar-17 7:39am

sir, post a question, someone will answer , i am going out now..

Member 12605293 27-Mar-17 1:34am

Hi Karthik
Good Morging :)

Karthik_Mahalingam 27-Mar-17 1:40am

good morning

Member 12605293 27-Mar-17 3:08am

Hi karthik
I am just enhancing the asp.net grid which you have helped me few weeks ago,by adding a dropdown into the bound column and the details of dropdown is linked using Join Query,but after bind the ddl the ID is not showing in code behind also need some ideas how to get only the Id of that column while joining in my gridtable

Karthik_Mahalingam 27-Mar-17 4:02am

map datavaluefield as ID

Member 12605293 10-Mar-17 6:49am

I have used the same code which was done last week for Gridview in asp
now I have just changed made the connection string in aspx page as well as in cs page
Here is my cs

<telerik:RadScriptManager runat="server" ID="RadScriptManager1" />
<telerik:RadSkinManager ID="RadSkinManager1" runat="server" ShowChooser="true" />
<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
<ajaxsettings>
<telerik:AjaxSetting AjaxControlID="Button1">
<updatedcontrols>
<telerik:AjaxUpdatedControl ControlID="Label1" />

<telerik:RadComboBox RenderMode="Classic" ID="RadComboBox1" Text="Select" runat="server"
CheckBoxes="true" EnableCheckAllItemsCheckBox="true" MarkFirstMatch="true" HighlightTemplatedItems="true"
AutoPostBack="true" ValueField="--Select--" OnSelectedIndexChanged="RadComboBox1_SelectedIndexChanged"
> <%--HighlightTemplatedItems="true" OnClientItemsRequested="UpdateItemCountField"
OnDataBound="RadComboBox1_DataBound" OnItemDataBound="RadComboBox1_ItemDataBound"
OnItemsRequested="RadComboBox1_ItemsRequested" DropDownCssClass="exampleRadComboBox"> --%>
<items>

<telerik:RadComboBoxItem Text="Dotnet" />
<telerik:RadComboBoxItem Text="Java" />
<telerik:RadComboBoxItem Text="Sales" />
<telerik:RadComboBoxItem Text="Hr" />
<telerik:RadComboBoxItem Text="Admin" />

<telerik:RadComboBox RenderMode="Lightweight" runat="server" ID="RadComboBox2" style="margin-left:671px;margin-bottom:24px;width:250px"
DataSourceID="SqlDataSource1" AutoPostBack="true" Text="Select" MarkFirstMatch="true" EnableLoadOnDemand="true" HighlightTemplatedItems="true"
ValueField="--Select--"
OnDataBound="RadComboBox2_DataBound" OnItemDataBound="RadComboBox2_ItemDataBound"
OnSelectedIndexChanged="RadComboBox2_SelectedIndexChanged">
<headertemplate>

Employee ID
Employee Name
Salary
Department
Age

<itemtemplate>

<%#DataBinder.Eval(Container.DataItem,"EmpId") %>

<%#DataBinder.Eval(Container.DataItem,"EmpName") %>

<%#DataBinder.Eval(Container.DataItem,"Sal") %>

<%#DataBinder.Eval(Container.DataItem,"Dep") %>

<%#DataBinder.Eval(Container.DataItem,"Age") %>

<footertemplate>
A total of
<asp:Literal runat="server" ID="RadComboItemsCount" />
items

<telerik:RadButton RenderMode="Lightweight" runat="server" ID="Button1" Text="Select" OnClick="Button1_Click" >
<asp:Label runat="server" ID="Label1" />

<telerik:RadGrid ID="RadGrid1" ShowStatusBar="true" margin-top="-46px" Height="500px" runat="server"

F-ES Sitecore 10-Mar-17 5:32am

This question is asked every day, please do basic research like using google before you post a question.

2 solutions

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ZurdoDev · Accepted Answer · 2017-03-10T01:12:00

Solution 1

You have this in web.config:

<add name="SST321ConnectionString"

and then you try to reference it like this:

ConfigurationManager.ConnectionStrings["sqlconnection"].ConnectionString

You don't have a connection string named "sqlconnection." You have one named "SST321ConnectionString"

Posted 10-Mar-17 1:12am

ZurdoDev

Karthik_Mahalingam · Accepted Answer · 2017-03-10T01:13:00

Solution 2

change the connection string name

SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["SST321ConnectionString"].ConnectionString);

Posted 10-Mar-17 1:13am

Karthik_Mahalingam