DropDownList in Datagrid

I get a DataBinding: 'System.Data.DataRowView' does not contain a property with the name 'priority_id'. error message when I click the edit button on DataGrid. I am not quite sure what is going on. I am relatively new to this and followed the direction in my book but it still does not work. Below is my code. Any help would be appreciated.

<%@ Page Language="VB" MasterPageFile="~/masters/leftnavbar_maint_tasks.master" AutoEventWireup="false" CodeFile="sub_priority_types.aspx.vb" Inherits="maint_sub_priority_types" title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="cphMain" Runat="Server">
<h4>Add Sub-Priority Type...</h4>
    <asp:formview id="frmAddSubPriority" runat="server" datakeynames="id" datasourceid="srcSubPriority" defaultmode="Insert">
        <edititemtemplate>
            id:
            <asp:label id="idLabel1" runat="server" text='<%# Eval("id") %>'></asp:label><br />
            desc:
            <asp:textbox id="descTextBox" runat="server" text='<%# Bind("desc") %>'>
            </asp:textbox><br />
            priority_id:
            <asp:textbox id="priority_idTextBox" runat="server" text='<%# Bind("priority_id") %>'>
            </asp:textbox><br />
            weight:
            <asp:textbox id="weightTextBox" runat="server" text='<%# Bind("weight") %>'>
            </asp:textbox><br />
            <asp:linkbutton id="UpdateButton" runat="server" causesvalidation="True" commandname="Update"
                text="Update">
            </asp:linkbutton>
            <asp:linkbutton id="UpdateCancelButton" runat="server" causesvalidation="False" commandname="Cancel"
                text="Cancel">
            </asp:linkbutton>
        </edititemtemplate>
        <insertitemtemplate>
            desc:
            <asp:textbox id="descTextBox" runat="server" text='<%# Bind("desc") %>'></asp:textbox><br />
            priority_id:
            <asp:textbox id="priority_idTextBox" runat="server" text='<%# Bind("priority_id") %>'></asp:textbox><br />
            weight:
            <asp:textbox id="weightTextBox" runat="server" text='<%# Bind("weight") %>'></asp:textbox><br />
            <asp:linkbutton id="InsertButton" runat="server" causesvalidation="True" commandname="Insert"
                text="Insert"></asp:linkbutton>
            <asp:linkbutton id="InsertCancelButton" runat="server" causesvalidation="False" commandname="Cancel"
                text="Cancel"></asp:linkbutton>
        </insertitemtemplate>
        <itemtemplate>
            id:
            <asp:label id="idLabel" runat="server" text='<%# Eval("id") %>'></asp:label><br />
            desc:
            <asp:label id="descLabel" runat="server" text='<%# Bind("desc") %>'></asp:label><br />
            priority_id:
            <asp:label id="priority_idLabel" runat="server" text='<%# Bind("priority_id") %>'></asp:label><br />
            weight:
            <asp:label id="weightLabel" runat="server" text='<%# Bind("weight") %>'></asp:label><br />
            <asp:linkbutton id="EditButton" runat="server" causesvalidation="False" commandname="Edit"
                text="Edit"></asp:linkbutton>
            <asp:linkbutton id="DeleteButton" runat="server" causesvalidation="False" commandname="Delete"
                text="Delete"></asp:linkbutton>
            <asp:linkbutton id="NewButton" runat="server" causesvalidation="False" commandname="New"
                text="New"></asp:linkbutton>
        </itemtemplate>
    </asp:formview>
<h4>Current Sub-Priority Types...</h4>
    <asp:gridview id="grdSubPriorities" runat="server" allowsorting="True" autogeneratecolumns="False" datasourceid="srcSubPriority">
        <columns>
            <asp:commandfield showeditbutton="True" />
            <asp:templatefield headertext="Description">
                <itemtemplate><%# Eval("desc") %></itemtemplate>
                <edititemtemplate>
                    <asp:textbox id="txtSubDesc" text='<%# Bind("desc") %>' runat="server"></asp:textbox>
                </edititemtemplate>
            </asp:templatefield>
            <asp:templatefield headertext="Weighting">
                <itemtemplate><%# Eval("weight") %></itemtemplate>
                <edititemtemplate>
                    <asp:textbox id="txtDesc" text='<%# Bind("weight") %>' runat="server"></asp:textbox>
                </edititemtemplate>
            </asp:templatefield>
            <asp:templatefield headertext="Priority">
                <itemtemplate><%#Eval("priority")%></itemtemplate>
                <edititemtemplate>
                    <asp:dropdownlist
                        id="ddlPriority"
                        datasourceid="srcPriority"
                        datatextfield="desc"
                        datavaluefield="id"
                        selectedvalue='<%#Bind("priority_id") %>'
                        runat="server">
                    </asp:dropdownlist>
                </edititemtemplate>
            </asp:templatefield>
        </columns>
    </asp:gridview>
    <asp:sqldatasource id="srcSubPriority" runat="server" conflictdetection="CompareAllValues" connectionstring="<%$ ConnectionStrings:conMaintTasks %>"
        insertcommand="INSERT INTO [sub_priority] ([desc], [priority_id], [weight]) VALUES (@desc, @priority_id, @weight)"
        oldvaluesparameterformatstring="original_{0}"
        selectcommand="SELECT sub_priority.id, sub_priority.[desc], sub_priority.weight,
                    priority.[desc] AS priority FROM sub_priority
                    JOIN priority ON sub_priority.priority_id = priority.id"
        updatecommand="UPDATE [sub_priority] SET [desc] = @desc, [priority_id] = @priority_id,
                    [weight] = @weight WHERE [id] = @id">
        <updateparameters>
            <asp:parameter name="id" type="Int32" />
            <asp:parameter name="desc" type="String" />
            <asp:parameter name="priority_id" type="Int32" />
            <asp:parameter name="weight" type="Byte" />
        </updateparameters>
        <insertparameters>
            <asp:parameter name="desc" type="String" />
            <asp:parameter name="priority_id" type="Int32" />
            <asp:parameter name="weight" type="Byte" />
        </insertparameters>
    </asp:sqldatasource>
    <asp:sqldatasource
        id="srcPriority"
        runat="server"
        connectionstring="<%$ ConnectionStrings:conMaintTasks %>"
        selectcommand="SELECT [id], [desc] FROM [priority]">
    </asp:sqldatasource>
</asp:Content>