Assign default value to SQLDataReader column if null in ASP.Net

Hi NerakSeven,

Please refer below sample.

HTML

<asp:GridView runat="server" ID="gvNames" AutoGenerateColumns="false">
    <Columns>
        <asp:BoundField DataField="Name" HeaderText="Name" />
    </Columns>
</asp:GridView>

Namespaces

C#

using System.Data;
using System.Data.SqlClient;
using System.Configuration;

C#

Imports System.Data
Imports System.Data.SqlClient
Imports System.Configuration

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.Add("Name");
        string name;
        using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT * FROM Customers", con))
            {
                con.Open();
                SqlDataReader dr = cmd.ExecuteReader();
                while (dr.Read())
                {
                    if (!string.IsNullOrEmpty(dr["Name"].ToString()))
                    {
                        name = dr["Name"].ToString();
                    }
                    else
                    {
                        name = "0";
                    }
                    dt.Rows.Add(name);
                    // INSERT TO Table code.
                }
                con.Close();
            }
        }

        gvNames.DataSource = dt;
        gvNames.DataBind();
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    If Not Me.IsPostBack Then
        Dim dt As DataTable = New DataTable()
        dt.Columns.Add("Name")
        Dim name As String

        Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)

            Using cmd As SqlCommand = New SqlCommand("SELECT * FROM Customers", con)
                con.Open()
                Dim dr As SqlDataReader = cmd.ExecuteReader()

                While dr.Read()

                    If Not String.IsNullOrEmpty(dr("Name").ToString()) Then
                        name = dr("Name").ToString()
                    Else
                        name = "0"
                    End If

                    dt.Rows.Add(name)
                End While

                con.Close()
            End Using
        End Using

        gvNames.DataSource = dt
        gvNames.DataBind()
    End If
End Sub

Screenshot