This is really driving me crazy. I've got a button inside a gridview to remove that item from the gridview (its datasource is a list). I've got the list being saved to session anytime a change is being made to it, and on page_load check if that session variable is empty, if not, then set that list to bind to the gridview.
Code开发者_开发技巧 Behind:
Public accomplishmentTypeDao As New AccomplishmentTypeDao()
Public accomplishmentDao As New AccomplishmentDao()
Public userDao As New UserDao()
Public facultyDictionary As New Dictionary(Of Guid, String)
Public facultyList As New List(Of User)
Public associatedFaculty As New List(Of User)
Public facultyId As New Guid
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'If Not Session("associatedFaculty") Is Nothing Then'
' Dim associatedFacultyArray As User() = DirectCast(Session("associatedFaculty"), User())'
' associatedFaculty = associatedFacultyArray.ToList()'
'End If'
Page.Title = "Add a New Faculty Accomplishment"
ddlAccomplishmentType.DataSource = accomplishmentTypeDao.getEntireTable()
ddlAccomplishmentType.DataTextField = "Name"
ddlAccomplishmentType.DataValueField = "Id"
ddlAccomplishmentType.DataBind()
facultyList = userDao.getListOfUsersByUserGroupName("Faculty")
For Each faculty As User In facultyList
facultyDictionary.Add(faculty.Id, faculty.LastName & ", " & faculty.FirstName)
Next
If Not Page.IsPostBack Then
ddlFacultyList.DataSource = facultyDictionary
ddlFacultyList.DataTextField = "Value"
ddlFacultyList.DataValueField = "Key"
ddlFacultyList.DataBind()
End If
gvAssociatedUsers.DataSource = associatedFaculty
gvAssociatedUsers.DataBind()
End Sub
Protected Sub deleteUser(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.CommandEventArgs)
facultyId = New Guid(e.CommandArgument.ToString())
associatedFaculty.Remove(associatedFaculty.Find(Function(user) user.Id = facultyId))
Session("associatedFaculty") = associatedFaculty.ToArray()
gvAssociatedUsers.DataBind()
upAssociatedFaculty.Update()
End Sub
Protected Sub btnAddUser_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnAddUser.Click
facultyId = New Guid(ddlFacultyList.SelectedValue)
associatedFaculty.Add(facultyList.Find(Function(user) user.Id = facultyId))
Session.Add("associatedFaculty", associatedFaculty.ToArray())
gvAssociatedUsers.DataBind()
upAssociatedFaculty.Update()
End Sub
Protected Sub Delete(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.CommandEventArgs)
End Sub
End Class
Markup:
<asp:UpdatePanel ID="upAssociatedFaculty" runat="server"
UpdateMode="Conditional">
<ContentTemplate>
<p><b>Created By:</b> <asp:Label ID="lblCreatedBy" runat="server"></asp:Label></p>
<p><b>Accomplishment Type: </b><asp:DropDownList ID="ddlAccomplishmentType" runat="server"></asp:DropDownList></p>
<p><b>Accomplishment Applies To: </b><asp:DropDownList ID="ddlFacultyList" runat="server"></asp:DropDownList>
<asp:Button ID="btnAddUser" runat="server" Text="Add Faculty" OnClientClick="incrementCounter();" /></p>
<p>
<asp:GridView ID="gvAssociatedUsers" runat="server" AutoGenerateColumns="false"
GridLines="None" ShowHeader="false">
<Columns>
<asp:BoundField DataField="Id" HeaderText="Id" Visible="False" />
<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<span style="margin-left: 15px;">
<p><%#Eval("LastName")%>, <%#Eval("FirstName")%>
<asp:Button ID="btnUnassignUser" runat="server" CausesValidation="false"
CommandArgument='<%# Eval("Id") %>' CommandName="Delete" OnCommand="deleteUser" Text='Remove' /></p>
</span>
</ItemTemplate>
</asp:TemplateField>
</Columns>
<EmptyDataTemplate>
<em>There are currently no faculty associated with this accomplishment.</em>
</EmptyDataTemplate>
</asp:GridView>
</p>
</ContentTemplate>
</asp:UpdatePanel>
Now here is the crazy part I am simply boggled by, if I uncomment the If Not Session...
block of page_load, then deleteUser
will never fire when btnUnassignUser
is clicked. If I keep it commented out...it fires no problem, but then of course my list can never have more than one item since I am not loading the saved list from session into the gridview but just a fresh one. But the button click is being registered, because page_load is being stepped through again when I am viewing in debug mode, just deleteUser never fires.
Why is this happening?? And how can I fix it??
You don't want to keep rebinding the grid. You want the grid to have the datasource again, but not to be reset.
gvAssociatedUsers.DataSource = associatedFaculty
if (!Page.IsPostBack)
gvAssociatedUsers.DataBind()
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