Adding new column in exist table

Question

I am working on visual studio 2010 Professional, i have table and i want to add new column  and name the the column by get it from a form that contain texttbox, then i  enter column name and then click on add button and then i would have a new column added to my exist table 

Answer 1

Bind the DropDownList like normal (set DataSourceID, DataTextField, DataValueField), and <%BIND%> the SelectedValue field. AutoPostBack should be enabled. In the OnSelectedIndexChanged:

 protected void DropDownSelectedIndexChanged(object sender, EventArgs e)
{
    //http://programming.top54u.com/post/GridView-DropDownList-Update-SelectedValue-All-At-Once.aspx
    //http://www.codeproject.com/KB/webservices/db_values_dropdownlist.aspx

    DropDownList d = sender as DropDownList;
    if (d == null) return;

    //grab row that contains the drop down list
    GridViewRow row = (GridViewRow)d.NamingContainer;

    //pull data needed from the row (in this case we want the ID for the row)
    object ID = gridEntries.DataKeys[row.RowIndex].Values["tableID"];


    SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["SiteSqlServer"].ConnectionString);
    conn.Open();

    SqlCommand c = new SqlCommand("UPDATE table SET value = @v WHERE tableID = @id", conn);

    SqlParameter p = c.Parameters.Add("@id", SqlDbType.Int);
    p.Value = Convert.ToInt32(ID);

    p = c.Parameters.Add("@v", SqlDbType.Int);
    p.Value = Convert.ToInt32(d.SelectedValue);

    c.ExecuteNonQuery();

    //databind the gridview to reflect new data.
    gridEntries.DataBind();
}

more info