Visual WebPart Sample Code 2010.

Visual WebPart Ascx CS Code

using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;
using System.Data;

namespace TestVisualWebPart1.VisualWebPart1
{
    public partial class VisualWebPart1UserControl : UserControl
    {
        DataTable dt = new DataTable();
        DataSet dset = new DataSet();
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                sgvTest.DataSource = getData();
                sgvTest.DataBind();
            }

        }
        public DataSet getData()
        {
            try
            {
                dt.Columns.Add("Title");
                dt.Columns.Add("Status");
                dt.Columns.Add("Priority");
                SPWeb currentWeb = SPContext.Current.Web;
                SPList lstTasks = currentWeb.Lists["Tasks"];
                SPListItemCollection myColl = lstTasks.Items;
                if (myColl.Count > 0)
                {
                    foreach (SPListItem item in myColl)
                    {
                        string strTitle = item["Title"].ToString();
                        string strStatus = string.Empty;
                        string strPriority = string.Empty;
                        if (item["Status"].ToString() != "")
                        {
                            strStatus = item["Status"].ToString();
                        }
                        else
                        {
                            strStatus = "DNA";
                        }
                        if (item["Priority"].ToString() != "")
                        {
                            strPriority = item["Priority"].ToString();
                        }
                        else
                        {
                            strPriority = "DNA";
                        }
                        DataRow drow = dt.NewRow();
                        drow["Title"] = strTitle;
                        drow["Status"] = strStatus;
                        drow["Priority"] = strPriority;
                        dt.Rows.Add(drow);
                    }
                }
                dset.Tables.Clear();
                dset.Tables.Add(dt);
                return dset;
            }
            catch (Exception ex)
            {
                lblException.Text = ex.ToString();
                return null;
            }
        }
    }
}
Visual WebPart Ascx Code

<%@ 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="VisualWebPart1UserControl.ascx.cs" Inherits="TestVisualWebPart1.VisualWebPart1.VisualWebPart1UserControl" %>
<table width="100%">
<tr>
<td>
<asp:Label ID="lblException" runat="server"></asp:Label>
</td>
</tr>
<tr>
<td>
<SharePoint:SPGridView ID="sgvTest" AutoGenerateColumns="false" runat="server">
<Columns>
<asp:BoundField  DataField="Title" HeaderText="Title"  />
<asp:BoundField  DataField="Status" HeaderText="Status" />
<asp:BoundField  DataField="Priority" HeaderText="Priority" />
</Columns>
</SharePoint:SPGridView>
</td>
</tr>
</table>