Retrieving list data using CAML to display in gridview

Question: What is retrieving list data using CAML?
 

In simple terms "It enables retrieve list data using SPQuery with CAML based notation".
Step 1: Open SharePoint 2010 Central Administration and navigate to a specific site.

Step 2: Open up Visual Studio 2012 and try to "SharePoint Visual Web Part" project, as in:

Step 3: Select "Deploy as a farm solution" as in the following and click the "Finish" button.

 

Step 4: The complete code of visualwebpart1usercontrol.ascx looks like this:

<%@ Assembly Name="$SharePoint.Project.AssemblyFullName$" %>

<%@ Assembly Name="Microsoft.Web.CommandUI, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>

<%@ Register TagPrefix="SharePoint" Namespace="Microsoft.SharePoint.WebControls"

    Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>

<%@ Register TagPrefix="Utilities" Namespace="Microsoft.SharePoint.Utilities" Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>

<%@ Register TagPrefix="asp" Namespace="System.Web.UI" Assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" %>

<%@ Import Namespace="Microsoft.SharePoint" %>

<%@ Register TagPrefix="WebPartPages" Namespace="Microsoft.SharePoint.WebPartPages"

    Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>

<%@  Control Language="C#" AutoEventWireup="true" CodeBehind="VisualWebPart1.ascx.cs"

    Inherits="RetrieveListDataUsingCAML.VisualWebPart1.VisualWebPart1" %>

<div>

    <table style="font-family: Verdana; text-align: center;">

        <tr>

            <td colspan="2">

                <asp:label id="Label1" runat="server" text="Select List Data Using CAML - SharePoint 2010 via Visual Studio 2012"

                    font-bold="true" forecolor="Maroon" font-size="Large"></asp:label>

            </td>

        </tr>

        <tr>

            <td colspan="2">

                <asp:button id="Button1" runat="server" text="Retrieve List Data - CAML" forecolor="Orange"

                    font-bold="true" backcolor="Black" onclick="Button1_Click" width="261px" />

            </td>

        </tr>

        <tr>

            <td colspan="2">

                <asp:label id="Label4" runat="server" font-bold="true"></asp:label>

            </td>

        </tr>

        <tr>

            <td align="center">

                <br />

                <br />

                <asp:gridview id="GridView1" runat="server" backcolor="LightGoldenrodYellow" bordercolor="Tan"

                    borderwidth="1px" cellpadding="2" enablemodelvalidation="True" forecolor="Black"

                    gridlines="None" autogeneratecolumns="False"><AlternatingRowStyle BackColor="PaleGoldenrod"/><FooterStyle BackColor="Tan" /><HeaderStyle BackColor="Tan" Font-Bold="True" /><PagerStyleBackColor="PaleGoldenrod" ForeColor="DarkSlateBlue" HorizontalAlign="Center" /><SelectedRowStyleBackColor="DarkSlateBlue" ForeColor="GhostWhite" /><Columns><asp:BoundField DataField="ID"HeaderText="Student Id" ReadOnly="true" SortExpression="ID" /><asp:BoundField DataField="Title"HeaderText="First Name" ReadOnly="true" /><asp:BoundField DataField="LastName" HeaderText="Last Name"ReadOnly="true" /><asp:BoundField DataField="Age" HeaderText="Age" ReadOnly="true" /></Columns></asp:gridview>

            </td>

        </tr>

    </table>

</div>

Step 5: The complete code of visualwebpart1usercontrol.ascx.cs looks like this:

using Microsoft.SharePoint;

using System;

using System.ComponentModel;

using System.Web.UI.WebControls.WebParts;namespace RetrieveListDataUsingCAML.VisualWebPart1

{

    [ToolboxItemAttribute(false)]

    public partial class VisualWebPart1 : WebPart

   

    {// Uncomment the following SecurityPermission attribute only when doing Performance Profiling using

        // the Instrumentation method, and then remove the SecurityPermission attribute when the code is ready

        // for production. Because the SecurityPermission attribute bypasses the security check for callers of

        // your constructor, it's not recommended for production purposes.

        // [System.Security.Permissions.SecurityPermission(System.Security.Permissions.SecurityAction.Assert, UnmanagedCode = true)]

        public VisualWebPart1()

        {

        }

        protected override void OnInit(EventArgs e)

        {

            base.OnInit(e);

            InitializeControl();

        }

        protected void Page_Load(object sender, EventArgs e)

        {

        }

        protected void Button1_Click(object sender, EventArgs e)

        {

            SPWeb web = SPContext.Current.Web;

            SPList list = web.Lists["Student"];

            SPQuery query = new SPQuery();

            query.ViewFields = "<FieldRef Name='ID'/>" +"<FieldRef Name='Title'/>" + "<FieldRef Name='LastName'/>" +"<FieldRef Name='Age'/>";

            SPListItemCollection item = list.GetItems(query);

            GridView1.DataSource = item.GetDataTable();

            GridView1.DataBind();

        }

    }

}

Step 6: Deploy the solution file and add the new webpart to a SharePoint site.

Step 7: The output of the application looks like this:

 

Step 8: The list data output of the application looks like this: