how to retrieve data from database in asp.net using c#

For this, just follow some simple steps which is given bellow.

1. Open Visual studio, goto file --> click New Web site --> select lcocation --> select C# as your language..
2. Open Default.aspx and Drag Gridview from ToolBar menu (Standard Control)
3. Or copy bellow code on to your .aspx form between <DIV></DIV> tag.
   
   
   <asp:GridView ID="GridView1" runat="server" DataKeyNames="ACODE"
   AutoGenerateColumns = "False" onrowdatabound="GridView1_RowDataBound"
   ShowFooter="True" BackColor="White" BorderColor="#336666"
   BorderStyle="Double" BorderWidth="3px" CellPadding="4" GridLines="Horizontal">
   
   

   <FooterStyle BackColor ="White" ForeColor="#333333" />

   <RowStyle BackColor="White" ForeColor="#333333" />

   <Columns>

   <asp:BoundField DataField="ACODE" HeaderText="Product ID" />

   <asp:BoundField DataField="PRD_NAME" HeaderText="Product Name" />

   <%
   

   -- <asp:BoundField DataField="QTY" HeaderText="Quantity" />--%>

   <asp:TemplateField HeaderText = "Quantity">

   <ItemTemplate>

   <asp:Label ID="LblQty" runat="server" Text='<%# Bind("QTY") %>'></asp:Label>

   </ItemTemplate>

   <FooterTemplate >

   <asp:Label ID="LblSumQty" runat="server" Text="1"></asp:Label>

   </FooterTemplate>

   </asp:TemplateField>

   </Columns>

   <PagerStyle BorderStyle="None" BackColor="#336666" ForeColor="White"

   HorizontalAlign="Center" />

   <SelectedRowStyle BackColor="#339966" Font-Bold="True" ForeColor="White" />

   <HeaderStyle BackColor="#336666" Font-Bold="True" ForeColor="White" />

   </asp:GridView>


4. Now, Open your Default.aspx.cs page and paste bellow code and change credentials according to your system and Sql Server.. 

public static int SQty = 0;
protected void Page_Load(object sender, EventArgs e)
{

if (!IsPostBack)
{
viewData();
}

}
public void viewData()
{

string strconn = "data source = INTEL-PC\\SQLEXPRESS; database = JagritiA; user id = sa; password = sa;"; // change this according to your sytem database name and password.
SqlConnection sqlconn = new SqlConnection(strconn);
sqlconn.Open();
try
{

string strQuery = "select top 10 ACODE, PRD_NAME, MATCODE as QTY from tblmst_product where Matcode = 02"; //change this select query according to your databse table
SqlDataAdapter sqlDA = new SqlDataAdapter(strQuery, sqlconn);
DataSet ds = new DataSet();

       sqlDA.Fill(ds, "Product");
       GridView1.DataSource = ds;
       GridView1.DataBind();

}
catch (Exception ex)
{

throw ex;

}
finally
{

sqlconn.Close();

} 

}

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{

DataRowView dtview = e.Row.DataItem as DataRowView;
if (e.Row.RowType == DataControlRowType.DataRow)
{
Label lbl1 = (Label)e.Row.Cells[2].FindControl("LblQty");
SQty = SQty +
Convert.ToInt32(lbl1.Text);
}
if (e.Row.RowType == DataControlRowType.Footer)
{

e.Row.Cells[1].Text =
"Total : ";
e.Row.Cells[2].Text =
Convert.ToString(SQty);

}

}

Now if u run this, it will look like..