Error on selecting initial value in Displaying gridview based on drop down list selection

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When user selects the initial value Please Select I get an exception which is.
Conversion failed when converting the nvarchar value 'Please Select' to data type int.
The Initial value has to be added programmatically
How do I fix the error,below is my code which works correctly except if the initial value is selected.

C#

protected void Page_Load(object sender, EventArgs e)
    {
        if(!Page.IsPostBack)
        {
        string cn = ConfigurationManager.ConnectionStrings["connectivity"].ConnectionString;
        using(SqlConnection connection=new SqlConnection(cn))
        {
           
            SqlCommand command = new SqlCommand("select * from Employees",connection);
            connection.Open();
            //command.Parameters.AddWithValue("@id",DropDownList1.SelectedValue);
            SqlDataReader dr = command.ExecuteReader();
            DropDownList1.DataTextField = "name";
            DropDownList1.DataValueField = "id";
            DropDownList1.DataSource = dr;
            DropDownList1.DataBind();
            ListItem li = new ListItem("Please Select");
            DropDownList1.Items.Insert(0, li); 
        }
    }
    }
    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        string cn = ConfigurationManager.ConnectionStrings["connectivity"].ConnectionString;
        using (SqlConnection connection = new SqlConnection(cn))
        {
            SqlCommand command = new SqlCommand("select * from Employees where id=@id", connection);
            connection.Open();
            command.Parameters.AddWithValue("@id",DropDownList1.SelectedValue);
            SqlDataReader dr = command.ExecuteReader();
            GridView1.DataSource = dr;
            GridView1.DataBind();

        }
    }

Posted 17-Jun-13 6:48am

Member 9176543

Updated 17-Jun-13 7:09am

Thanks7872

v4

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Comments

Ariana Bond 17-Jun-13 12:59pm

When you are adding initial value to dropdownlist typecast error occurred, try to the replace initial value add code as follows--
DropDownList1.Items.Insert(0, new System.Web.UI.WebControls.ListItem("Please Select", "0"));

Member 9176543 18-Jun-13 1:43am

And if a user selects the initial value then how to
Display a messsge ,"No Record Selected"

Thanks7872 18-Jun-13 1:47am

To display message,set EmptyDataText="No Record Selected" in gridview definition.

Member 9176543 18-Jun-13 2:09am

Thanks Ariana and Rohan.

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Thanks7872 · Accepted Answer · 2013-06-17T07:22:00

Bind your dropdown like

C#

SqlCommand command = new SqlCommand("select * from Employees",connection);
connection.Open();
SqlDataAdapter da=new SqlDataAdapter(command);
DataSet ds=new DataSet();
da.fill(ds);
DropDownList1.DataSource =ds; 
DropDownList1.DataBind();

in if(!Page.IsPostBack) as well as DropDownList1_SelectedIndexChanged

and define selected value of dropdown in definition itself. No need to make it in this code.

Regards.. :)