Question

  <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
      ConnectionString="<%$ ConnectionStrings:FlowServerConnectionString %>" 
      SelectCommand="SELECT [RepGroup_Name], [RepGroup_ID] FROM [Rep_Group] WHERE [RepGroup_ID] in
            (SELECT [ID_RepGroup]
            FROM [FlowServer].[dbo].[Rep_Permission]
            WHERE [ID_User]=@ID_User)">
      <SelectParameters>
          <asp:ProfileParameter DefaultValue="" Name="ID_User" PropertyName="UserName" />
      </SelectParameters>

How to insert System.Web.HttpContext.Current.User.Identity.Name to my property “ID_User” (it’s username here)

Answer 1

On your SqlDataSource1 add OnInit="SqlDataSource1_Init" then add the following event to the code behind:

protected void SqlDataSource1_Init(object sender, EventArgs e)
{
    this.SqlDataSource1.SelectParameters["ID_User"].DefaultValue = System.Web.HttpContext.Current.User.Identity.Name;
}