How to change the CSS class for a div in code-behind?

If your div has runat="server" then you directly use this:

divId.Attributes["class"] = "classname";

How to check atleast one checkbox is checked in asp.net ?

if (!chkListQualification.Items.Cast<ListItem>().Any(i => i.Selected))
{
  lblMessage.Text = "Please select at least one qualification.";
  return ;
}

Difference between IDENT_CURRENT, @@IDENTITY, SCOPE_IDENTITY in sqlserver ?

• IDENT_CURRENT returns the last identity value generated for a specific table in any session and any scope.
• @@IDENTITY returns the last identity value generated for any table in the current session, across all scopes.
• SCOPE_IDENTITY returns the last identity value generated for any table in the current session and the current scope.
• 
  

How to use Literal and Placeholder in asp.net ?

Design Page :-

       <div>

            <fieldset>

                <legend>Using Placeholder & Literals</legend>

                <asp:PlaceHolder ID="PlaceHolder1" runat="server" />

            <br />

                <asp:Literal ID="literalDemo" runat="server" />

            </fieldset>

</div>

Coding Page : -

Make class like this : -

        private static DataTable GetData()

        {

            DataTable dt = new DataTable();

            using (SqlConnection con = new SqlConnection(Common.Global.myconstring))

            {

                SqlDataAdapter adp = new SqlDataAdapter("GetData", con); //call procedure

                adp.Fill(dt);

            }

            return dt;

        }

        protected void Page_Load(object sender, EventArgs e)

        {

            DataTable dt = GetData();

            StringBuilder sb = new StringBuilder();

            sb.Append("<table>");

            sb.Append("<tr>");

            foreach (DataColumn col in dt.Columns)

            {

                sb.Append("<th>");

                sb.Append(col.ColumnName);

                sb.Append("</th>");

            }

            sb.Append("</tr>");

            foreach(DataRow dr in dt.Rows)

            {

                sb.Append("<tr>");

                foreach(DataColumn col in dt.Columns)

                {

                    sb.Append("<td>");

                    sb.Append(dr[col.ColumnName]);

                    sb.Append("</td>");

                }

                

                sb.Append("</tr>");

            }

            sb.Append("</html>");

            literalDemo.Text = sb.ToString();

            // you can also use this if you take placeholder in design page.

            PlaceHolder1.Controls.Add(new Literal { Text = sb.ToString() });

        }

Output:-

Can't find [WebInvoke] and [WebGet]

Need to add the reference System.ServiceModel.Web.dll and import the namespace System.ServiceModel.Web by using below statement using System.ServiceModel.Web; Then it will work.

[WebInvoke(BodyStyle = WebMessageBodyStyle.WrappedRequest, RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)]

[OperationContract]

[WebInvoke(Method = "POST", UriTemplate = "/Save")]

what is an array in c#?

Design Page : -

  <asp:Label ID="lblValue" runat="server" ForeColor="Red" />

Code Behind : -

// Multi dimensional Array

            string[] arr = new string[] { "abc", "def", "ghi", "jkl" };

            int[] num1 = new int[] { 0, 1, 2, 6, 6, 7, 4, 4, 4, 3 };

            lblValue.Text = arr[0] + " " + arr[1] + " " + arr[2] + " " + arr[3];

            // Single dimensional Array

            int[] num = new int[10] { 0, 1, 2, 6, 6, 7, 4, 4, 4, 3 };

            string[] j = new string[5] { "a", "b", "c", "d", "e" };

            lblValue.Text = Convert.ToString(abc(num));

            string[,] h = new string[3, 2] { { "Deepak", "Sharma" }, { "Hemal", "Kumar" }, { "Mahesh", "Yadav" } };

            lblValue.Text = h[0, 0] + " " + h[0, 1] + " " + h[1, 0] + " " + h[1, 1] + " " + h[2, 0] + " " + h[2, 1];

Mehod : -

  private int abc(int[] a)

        {

            return a[5] * 2;

        }

How to bind country list in dropdown using xml ?

Make dropdownlist : -

<asp:DropDownList ID="ddlCountry" runat="server" />

Make Country.xml : -

<?xml version="1.0" encoding="utf-8" ?>

  <CountryList>

    <country code="Afghanistan" iso="4"/>

    <country code="Albania" iso="8"/>

    <country code="Algeria" iso="12"/>

    <country code="Angola" iso="24"/>

    <country code="Anguilla" iso="660"></country>

    <country code="Antarctica" iso="10"></country>

    <country code="Antigua And Barbuda" iso="28"></country>

    <country code="Argentina" iso="32"></country>

    <country code="Armenia" iso="51"></country>

    <country code="Aruba" iso="533"></country>

  </CountryList>

Code- Behind:-

private void BindCountries()

        {

            DataSet ds = new DataSet();

            ds.ReadXml(MapPath("Country.xml"));

            DataView dv = ds.Tables[0].DefaultView;

            dv.Sort = "code";

            ddlCountry.DataTextField = "code";

            ddlCountry.DataValueField = "iso";

            ddlCountry.DataSource = dv;

            ddlCountry.DataBind();

            ddlCountry.Items.Insert(0, new ListItem("-Select-", "0"));

        }