Forms Data Controls :: Place Dropdown In Grid Show

I'm currently binding a simple grid and show. And a separate dropdown and show. Now I want to place dropdown in grid and bind also I will able to change value of dropdown and save.Problem in grid binding drop down not able to find datasource.my code as -

<asp:TemplateField HeaderText="REPORTING TO" Visible ="true" SortExpression="reporting_to">
<ItemTemplate>
<asp:Label ID="Lnk_ReportingTo" unat="server" text="<%# bind('reporting_to' ) %>" ></asp:Label>
</ItemTemplate>
</asp:TemplateField>
//Binding grid
public void BindData()
{
//Calling To Dal From BLL LAYER
DataSet ds = musergroupBLL.GetUserGroup(0, UserFk, 0);
Grd_UserRole.DataSource = ds;
Grd_UserRole.DataBind();
}
For dropdown fill in page on .aspx
<asp:DropDownList ID="DDManager" runat="server" onselectedindexchanged="DDManager_SelectedIndexChanged"></asp:DropDownList>
On .cs
protected void FillDD()
{
DataSet ds = MUsrBll.GetUser(MUsrolEnt);
DDManager.DataSource = ds;
DDManager.DataTextField = "usr_id";
DDManager.DataValueField = "usr_PK";
DDManager.DataBind();
}

Till here every thing is workingfor simple grid.

<asp:TemplateField HeaderText="REPORTING TO" Visible ="true" SortExpression="reporting_to">
<ItemTemplate>
<asp:Label ID="Lnk_ReportingTo" unat="server" text="<%# bind('reporting_to' ) %>" ></asp:Label>
</ItemTemplate>
</asp:TemplateField>

Now changing above code from below aspx code for dropdown place in grid. But not getting how to call datasource and selected value in grid. Data source is same as FillDD()function above for dropdown.

<asp:TemplateField HeaderText="REPORTING TO" Visible ="true" SortExpression="reporting_to">
<ItemTemplate>
<asp:DropDownList ID="Lnk_ReportingTo111" SelectedValue='<%# bind('reporting_to' )%>' DataSource = "<%# bind('usr_PK' )%>" DataTextField = "usr_id" DataValueField = "usr_PK" runat="server" ></asp:DropDownList>
</ItemTemplate>
</asp:TemplateField>