Retrieve Mastergridview using username

Hi,
I am trying to retrieve data in mastergrid using username but it's showing record for all the users instead of just login user
This is the code :
<asp:GridView ID="GridView1" DataSourceID="SqlDataSource1" DataKeyNames="UserName" AutoGenerateSelectButton="true" runat="server" /> <asp:DetailsView ID="DetailsView1" DefaultMode= "Edit" AutoGenerateEditButton="true" AutoGenerateInsertButton="true" AutoGenerateDeleteButton="true" DataSourceID="SqlDataSource2" runat="server"> </asp:DetailsView> <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$Connectionstrings:userConnectionString%>" SelectCommand="SELECT UserName, Quote_Name FROM Digitizing_Quotes"> </asp:SqlDataSource> <asp:Sql ...