Why the count of items in my ComboBox is always 0 although the datasource of this combobox has data !!
<div align="right" dir="rtl">
<asp:Label ID="lbl_contactListName" runat="server" Text="Menu Name :" CssClass="span"></asp:Label>
<telerik:RadComboBox ID="ddl_contactList" runat="server" AutoPostBack="True" CausesValidation="False"
CollapseDelay="0" Culture="ar-EG" ExpandDelay="0" Filter="StartsWith" ItemsPerRequest="10"
MarkFirstMatch="true" Skin="Outlook" EnableAutomaticLoadOnDemand="True" EmptyMessage="-New Menu-"
ShowMoreResultsBox="True" OnSelectedIndexChanged="ddl_contactList_SelectedIndexChanged"
EnableVirtualScrolling="True" DataTextField="list_desc" DataValueField="list_code"
DataSourceID="ObjectDataSource1" EnableViewState="true" Width="300px">
</telerik:RadComboBox>
</div>
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="GetContactListsByDep"
TypeName="SendSMS_EmailModule.ContactList">
<SelectParameters>
<asp:SessionParameter Name="year" SessionField="year" Type="Int32" />
<asp:SessionParameter Name="main_code" SessionField="main_code" Type="Int32" />
</SelectParameters>
</asp:ObjectDataSource>
The property value of of Rad combo "EnableAutomaticLoadOnDemand=True" here.This property load all the data on demand. So when you click on your combobox it will load the data in it untill that it is empty. If you do not want to make your combo on demand then Make that property false. By doing that you will get the count directly.
If you want to keep that EnableAutomaticLoadOnDemand property to True. you can use ItemDataBound event of the Rad Combo. By using it you can change the Item's Text and Value properties as well as modify its Attributes collection based on the DataItem
You will find more details at telerik rad combo. Let me know if you want more detail on this.
Perhaps you should call DataBind() before you call Count().
ddl_contactList.DataBind();
ddl_contactList.Items.Count();
Are you getting the Count as Zero on Page Load.
If that's the case it is because the page load event hits before the ComboBox is populated. An easier way is to populate the items on Page Load itself.
(This code is untested)
if(!Page.IsPostBack)
{
using(var context = new Entities())
{
foreach(var item in context.Employee)
{
RadComboBox1.Items.Add(new RadListBoxItem(item.Name, item.ID.ToString()));
}
}
}
//Here you can get the count.
I have two cascading dropdown lists I'm attempting to bind to two separate SqlDataSources each.
These dropdownlists exist in a FormView's EditItemTemplate. Inside the EditItemTemplate two sqldatasource controls exist that populate the department and the jobname. The DeptID and the JobID are the primary keys in those tables. This creates the "cascading effect" between departments and jobs. When a department is selected, only the jobs associated with that department appear.
This piece is working properly.
<asp:FormView ID="frmProfile" runat="server" DataSourceID="sqlDSProfile"
DataKeyNames="EUID" style="margin-top: 0px">
<EditItemTemplate>
<asp:DropDownList ID="ddlDepartments" runat="server" Width="135px"
DataSourceID="sqlDSDepartments"
DataTextField="Department"
DataValueField="DeptID" AutoPostBack="True"
SelectedValue='<%# Bind("CurrentDeptID") %>'
AppendDataBoundItems="true" >
<asp:ListItem></asp:ListItem>
</asp:DropDownList>
<asp:DropDownList ID="ddlJobNames" runat="server" Width="185px"
DataSourceID="sqlDSJobs" DataTextField="JobName" DataValueField="JobID"
SelectedValue='<%# Bind("CurrentJobID") %>'
AppendDataBoundItems="true" >
<asp:ListItem></asp:ListItem>
</asp:DropDownList>
<asp:SqlDataSource ID="sqlDSDepartments" runat="server"
ConnectionString="<%$ ConnectionStrings:JobsDB %>"
SelectCommand="SELECT tblDepartments.DeptID,
tblDepartments.Department
FROM tblDepartments" />
<asp:SqlDataSource ID="sqlDSJobs" runat="server"
ConnectionString="<%$ ConnectionStrings:JobsDB %>"
SelectCommand="SELECT tblJobs.JobID, tblJobs.JobName FROM tblJobs
INNER JOIN tblDeptsJobs ON tblDeptsJobs.JobID = tblJobs.JobID
WHERE tblDeptsJobs.DeptID = #DeptID" >
<SelectParameters>
<asp:ControlParameter ControlID="ddlDepartments" Name="DeptID"
PropertyName="SelectedValue" />
</SelectParameters>
</asp:SqlDataSource>
</EditItemTemplate>
</asp:FormView>
Outside the formview the SqlDataSource exists that binds all of the information to the Employee table in an update statement. I'm leaving all of the other information in this SqlDataSource even though it's been omitted from the FormView above.
<asp:SqlDataSource ID="sqlDSProfile" runat="server"
ConnectionString="<%$ ConnectionStrings:JobsDB %>"
SelectCommand="SELECT tblEmployee.EUID,
tblEmployee.DateHired,
tblEmployee.LastName,
tblEmployee.HiredLastName,
tblEmployee.FirstName,
tblEmployee.Role,
tblEmployee.JobGrade,
tblEmployee.CurrentDeptID,
tblDepartments.Department,
tblDepartments.DeptID,
tblEmployee.CurrentJobID,
tblJobs.JobName,
tblJobs.JobID,
tblEmployee.CurrentShift,
tblEmployee.JobDate,
tblEmployee.IsDisplaced,
tblEmployee.EligibilityDate
FROM tblEmployee
LEFT OUTER JOIN tblDepartments ON tblEmployee.CurrentDeptID = tblDepartments.DeptID
EFT OUTER JOIN tblJobs ON tblEmployee.CurrentJobID = tblJobs.JobID
WHERE (tblEmployee.EUID = #EUID)"
UpdateCommand="UPDATE [tblEmployee]
SET [tblEmployee].[DateHired] = #DateHired,
[tblEmployee].[LastName] = #LastName,
[tblEmployee].[HiredLastName] = #HiredLastName,
[tblEmployee].[FirstName] = #FirstName,
[tblEmployee].[Role] = #Role,
[tblEmployee].[JobGrade] = #JobGrade,
[tblEmployee].[CurrentDeptID] = #CurrentDeptID,
[tblEmployee].[CurrentJobID] = #CurrentJobID,
[tblEmployee].[CurrentShift] = #CurrentShift,
[tblEmployee].[JobDate] = #JobDate,
[tblEmployee].[IsDisplaced] = #IsDisplaced,
[tblEmployee].[EligibilityDate] = #EligibilityDate
WHERE [tblEmployee].[EUID] = #EUID"
ProviderName="System.Data.SqlClient">
<SelectParameters>
<asp:SessionParameter Name="EUID" SessionField="sProfileEUID" DbType="String" />
</SelectParameters>
<UpdateParameters>
<asp:Parameter Name="DateHired" DbType="Date" />
<asp:Parameter Name="LastName" DbType="String" />
<asp:Parameter Name="HiredLastName" DbType="String" />
<asp:Parameter Name="FirstName" DbType="String" />
<asp:Parameter Name="Role" DbType="String" />
<asp:Parameter Name="JobGrade" DbType="Byte" />
<asp:Parameter Name="CurrentDeptID" DbType="Int32" />
<asp:Parameter Name="CurrentJobID" DbType="Int32" />
<asp:Parameter Name="CurrentShift" DbType="Int32" />
<asp:Parameter Name="JobDate" DbType="Date" />
<asp:Parameter Name="IsDisplaced" DbType="Boolean"/>
<asp:Parameter Name="EligibilityDate" DbType="Date"/>
<asp:SessionParameter Name="EUID" SessionField="sProfileEUID" DbType="String" />
</UpdateParameters>
</asp:SqlDataSource>
The only pieces I can't figure out how to bind are the Departments and the Jobs. Everything else is working. I've tried using the following code in the DropDownList controls...
SelectedValue='<%# Bind("CurrentDeptID") %>'
SelectedValue='<%# Bind("CurrentJobID") %>'
...but these result in errors.
Summary
When the user clicks edit, I need the values in the two dropdownboxes to pull their selectedvalue from the main sqlDSProfile data source, but I need them to be updatable. I've gotten it to the point where I can update and bind the job that an associate belongs to, but because the dropdownlists cascade, when I attempt to change the department the AutoPostBack breaks the binding between sqlDSProfile - CurrentJobID and ddlJobs.
Update
I added tblEmployee.CurrentDeptID and tblEmployee.CurrentJobID to the select statement, and added Bind() statements to the DropDownList controls.
SelectedValue='<%# Bind("CurrentDeptID") %>'
SelectedValue='<%# Bind("CurrentJobID") %>'
The two DropDownLists are now populated with accurate information pulled from the Employee table, showing the department and job that the employee belongs to.
The two DropDownLists are also populated by the two SqlDataSources inside the FormView, giving me options for changing the department and changing the job.
When I change the Job, it works and the employees job is updated.
When I change the Department, it breaks saying DataBinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control.
Close to Done
I removed the data binding from ddlJobs and coded that in the background.
Protected Sub frmProfile_ItemUpdating(sender As Object, e As System.Web.UI.WebControls.FormViewUpdateEventArgs) Handles frmProfile.ItemUpdating
If frmProfile.CurrentMode = FormViewMode.Edit Then
e.NewValues("CurrentJobID") = DirectCast(DirectCast(sender, FormView).FindControl("ddlJobs"), DropDownList).SelectedValue
End If
End Sub
The only piece that's left is building the code for when the ddlDepartments changes.
pseudocode...
' If Item exists in ddlJobs Then
' select item (CurrentJobID)
' else
' select index 0 and make them pick something new
' end if
So Close!
Updated Again
This is the code I've developed to loosely bind this. In the page_load I'm trying to pull the contents of CurrentJobID from sqlDSProfile and check to see if that value exists in ddlJobs. If it does I want to set ddlJobs.SelectedValue = to that CurrentJobID. If it doesn't I want to set the selectedindex to 0 which is a message saying "pick one" or something.
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If frmProfile.CurrentMode = FormViewMode.Edit Then
' Need to determine if the CurrentJobID returned in the select statement
' exists in the ddlJobs dropdownlist. If it does, set that to the
' selectedvalue, if not set it to 0 so the user can select a new job.
Dim ddlJobs As DropDownList = frmProfile.FindControl("ddlJobs")
Dim dvProfile As DataView = sqlDSProfile.Select(DataSourceSelectArguments.Empty)
Dim drvProfile As DataRowView = dvProfile(0)
If ddlJobs.Items.FindByValue(drvProfile("CurrentJobID")) Is DBNull.Value Then
ddlJobs.SelectedIndex = 0
Else
ddlJobs.SelectedValue = drvProfile("CurrentJobID")
End If
End If
End Sub
Its returning a null reference exception on the line where I'm checking for dbnull.value
I had a similar issue and found a very simple resolution, (and in c#). Imagine a database with a table Questions, related to category and subcategory tables (which are also related and constrained). When trying to update existing records asp throws an error. This is the solution that I worked out thanks to the information above from Lucretius et al.
Only databind the parent dropdownlist
Find a way to insert the child dropdown selected value on the update event of the datasource.
As:
protected void odseditquestion_Updating(object sender, ObjectDataSourceMethodEventArgs e)
{
//dynamically assign value from ddlsubcategory to odseditquestion on updating event
//you really should not have to do this
DropDownList ddlsubcategory = (DropDownList)fveditquestion.FindControl("ddlsubcategory");
e.InputParameters["subcatid"] = (ddlsubcategory.SelectedValue);
}
It works on my application. Hope it helps somebody, this one cost me half a day, such is asp!!
The problem can be if tlbEmployee columns in the SqlDSProfile in the update statement and field names used by your controls do not match. Other procedures you've followed are right.
SqlDataSource control expects field names it updates to be similar
with those bound to the controls(fields) inside the DataBound control.
The Solution can be: change all the update Parameters to ControlParameters referencing the right control for each one
Update: Wait, I think the problem is your select statement of the SqlDSProfile should contain: CurrentDeptID and CurrentJobID. Try it:
<asp:SqlDataSource ID="sqlDSProfile" runat="server"
ConnectionString="<%$ ConnectionStrings:JobsDB %>"
SelectCommand="SELECT tblEmployee.EUID,
tblEmployee.DateHired,
tblEmployee.LastName,
tblEmployee.HiredLastName,
tblEmployee.FirstName,
tblEmployee.Role,
tblEmployee.JobGrade,
tblDepartments.Department,
tblJobs.JobName,
tblEmployee.CurrentShift,
tblEmployee.JobDate,
tblEmployee.IsDisplaced,
tblEmployee.EligibilityDate
tblEmployee.CurrentDeptID,
tblEmployee.CurrentJobID
FROM tblEmployee
Advice: Test your code portion by portion.
Try the code without the dropdownlist, Test separately
Add the one drop downlist
Use select * from ... in select queries
Avoid ajax when testing
If you make it
Add portions of code portion after portion
at last use the partial updating (ajax)
I have a working solution now, thanks in part to Nuux and a bunch of online research. The tip about the join statement wasn't relevant, but the tip about including "CurrentJobID" and "CurrentDeptID" in my select query was spot on.
In addition to that I had to rework the controls a little. The two cascading dropdownlists are below. The ddlJobs dropdown list behaves like a normal databound control, but it doesn't have the Bind("CurrentJobID") statement I was trying in my original post.
<asp:DropDownList ID="ddlDepartments" runat="server" Width="185px"
DataSourceID="sqlDSDepartments"
DataTextField="Department"
DataValueField="DeptID"
SelectedValue='<%# Bind("CurrentDeptID") %>'
AppendDataBoundItems="true"
AutoPostBack="True" >
<asp:ListItem Text="--Select One--" Value="" />
</asp:DropDownList>
<asp:DropDownList ID="ddlJobs" runat="server" Width="185px"
DataSourceID="sqlDSJobs"
DataTextField="JobName"
DataValueField="JobID"
AppendDataBoundItems="true"
OnDataBinding="ddlJobs_DataBinding" />
The only thing the custom routine "ddlJobs_DataBinding" is doing is adding "--Select One--" as index 0 in the ddlJobs dropdown. I tried this in several places, like page_load, and the databound event of the formview with no success.
Protected Sub ddlJobs_DataBinding(sender As Object, e As System.EventArgs)
Dim ddlJobs As DropDownList = frmProfile.FindControl("ddlJobs")
Dim liSelectOne As New ListItem("--Select One--", 0)
ddlJobs.Items.Clear()
ddlJobs.Items.Insert(0, liSelectOne)
End Sub
The databound event of the formview frmProfile_DataBound event does do some work though. When the user clicks "edit" on the formview to enter editing mode this ensures that the dropdownlist ddlJobs has the correct job selected by default for the profile in question. If the user hasn't been assigned to a job then it defaults to selectedindex 0 which is "--Select One--" set in custom databinding event just above.
Protected Sub frmProfile_DataBound(sender As Object, e As System.EventArgs) Handles frmProfile.DataBound
If frmProfile.CurrentMode = FormViewMode.Edit Then
Dim ddlJobs As DropDownList = frmProfile.FindControl("ddlJobs")
Dim dvProfile As DataView = sqlDSProfile.Select(DataSourceSelectArguments.Empty)
Dim drProfile As DataRow = dvProfile.Table.Rows(0)
If drProfile("CurrentJobID").ToString() = "" Then
ddlJobs.SelectedIndex = 0
Else
ddlJobs.SelectedValue = drProfile("CurrentJobID").ToString()
End If
End If
End Sub
Finally, if the user selects a new job from ddlJobs, that value has to be fed to the database, which the ItemUpdating event of the formview handles.
Protected Sub frmProfile_ItemUpdating(sender As Object, e As System.Web.UI.WebControls.FormViewUpdateEventArgs) Handles frmProfile.ItemUpdating
If frmProfile.CurrentMode = FormViewMode.Edit Then
Dim ddlJobs As DropDownList = frmProfile.FindControl("ddlJobs")
e.NewValues("CurrentJobID") = ddlJobs.SelectedValue
End If
End Sub
Done!
For example, I have a gridview and two textboxes.
One textbox is for the text to search for.
The second textbox is an order number to search for.
I want my gridview to populate based on one or the other. I don't know how to tell my form if the user is using a number search by that and if a name, instead search by that.
Thanks for any help.
OK hope you haven't solved this yet because I took a few minutes to come up with an example that I think will do pretty much what you want.
DB access uses a stored procedure but you can use a ObjectDataSource with DAL, or just inline the SQL statement on the SqlDataSource, etc.
Markup:
Product ID:
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:CompareValidator ID="CompareValidator1" ControlToValidate="TextBox1" runat="server" ErrorMessage="You must enter a number"
ValidationGroup="vg1" Type="Integer" Operator="DataTypeCheck"></asp:CompareValidator>
<br />
Description:
<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><br />
<asp:Button ID="cmdSearch" runat="server" Text="Search" ValidationGroup="vg1" /><br />
<asp:GridView ID="GridView1" runat="server" DataSourceID="SqlDataSource1">
</asp:GridView>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" SelectCommand="spGetProducts"
CancelSelectOnNullParameter="False" SelectCommandType="StoredProcedure">
<SelectParameters>
<asp:ControlParameter ControlID="TextBox1" PropertyName="Text" DbType="String" DefaultValue="" />
<asp:ControlParameter ControlID="TextBox2" PropertyName="Text" DbType="Int32" DefaultValue="" />
</SelectParameters>
</asp:SqlDataSource>
And T-SQL for your query:
CREATE PROCEDURE spGetProducts
#ProductId int = NULL
,#ProductDescription nvarchar(100) = NULL
AS
BEGIN
SELECT [ProductId]
,[ProductDescription]
FROM [Products]
WHERE (
(
(#ProductId IS NULL)
OR
([ProductId] LIKE % + #ProductId + %)
)
AND
(
(#ProductDescription IS NULL)
OR
([ProductDescription] LIKE % + #ProductDescription + %;)
)
);
END
If the user doesn't enter anything in either of the fields, the SqlDataSource will still bind due to SqlDataSource.CancelSelectOnNullParameter = False but the empty parameter will not be sent with the query due to ControlParameter.DefaultValue being set. The stored procedure will then insert the NULL value into the parameter and basically skip that part of the filtering in the WHERE clause.
Hope this helps.
You can check the textboxes by using (TextBox1.Text.Trim.Length > 0) or (TextBox1.Text = "")
It sounds like what you are really asking is how do you filter your data source based on more than one possible filter parameter. Explaining that would require knowing what your data source is. Either way, the gridview is just going to display the filtered results, right?
If you are using SQL for your data source the technique is going to be totally different than filtering a collection in memory. So more information on that would be helpful.
I am using an EntityDataSource with a FormView on VB.NET application. The FormView contains an AjaxControlToolKit TabContains with multiple tabs. Due to the fact that each tab is a naming container, Bind doesn't work properly for updating values (as discovered from reading other posts on stackoverflow). I instead have to declare UpdateParameters on my EntityDataSource. Example markup is as follows:
<asp:FormView ID="fv" runat="server" DataSourceID="eds" DataKeyNames="ID">
<EditItemTemplate>
<asp:TabContainer ID="tc" runat="server">
<asp:TabPanel ID="tp" runat="server" HeaderText="Tab 1">
<ContentTemplate>
<asp:TextBox ID="tbName" runat="server" Text='<%#Eval("Name") %>'></asp:TextBox>
</ContentTemplate>
</asp:TabPanel>
</asp:TabContainer>
</EditItemTemplate>
</asp:FormView>
<asp:EntityDataSource ID="eds" runat="server" ConnectionString="name=NDSEntities"
DefaultContainerName="NDSEntities" EnableFlattening="False" EntitySetName="Customers"
Where="it.ID = #ID" EnableUpdate="true" EnableInsert="true">
<WhereParameters>
<asp:QueryStringParameter Name="ID" QueryStringField="ID" DbType="Guid" />
</WhereParameters>
<UpdateParameters>
<asp:ControlParameter Name="Name" ControlID="fv$tc$tp$tbName" DbType="String" />
</UpdateParameters>
<InsertParameters>
<asp:ControlParameter Name="Name" ControlID="fv$tc$tp$tbName" DbType="String" />
</InsertParameters>
</EntityDataSource>
This works great, until a customer is edited and their name is set to nothing (assuming in this case, a null name is allowed). The Name UpdateParameter is set to Null but the ObjectStateEntry is not set to modified for Null properties, even if previously the Entity had a value specified. As long as the name is changed to something other than Null, everything is updated correctly.
I found a workaround by putting the following code in the Updating event of the EntityDataSource.
Dim ose As ObjectStateEntry = context.ObjectStateManager.GetObjectStateEntry(action)
For Each p As Parameter In eds.UpdateParameters
ose.SetModifiedProperty(p.Name)
Next
This makes sure that each property in the UpdateParameters has its state set to modified. It works, but it seems like a hack and I can see it causing problems down the road. Is there anything else I could do?
Do you have an "Concurrency Mode" set for the entity in question? Depending on how you actually update the entity (I haven't used the EntityDataSource, but I'm guessing it internally uses the ObjectContext.Attach method), the code that creates the SQL statement, will try to update only those columns that are actually changed.
Consider the following:
void UpdatePersonEntity(int id, string firstName, string lastName)
{
Person p = new Person { Id = id };
this.Context.People.Attach(p);
p.FirstName = firstName;
p.LastName = lastName;
this.Context.SaveChanges();
}
If firstName or lastName is null, the ObjectContext would assume that it's original value hasn't been touched. This might be something you should look into. I apologize if this isn't helpful, but it might push you in the right direction.
I'm trying to create a LinqDataSource to bind to a DropDownList in an ASP.NET form. I only want to show the elements according to a date (which is one of the fields in the database).
Basically, the elements I want to show are the ones that will happen in the futures (i.e. after DateTime.Now).
I was trying the following markup :
<asp:DropDownList runat="server" ID="DropDownList1"
AppendDataBoundItems="True" DataSourceID="LinqDataSource1"
DataTextField="TextField" DataValueField="ValueField">
</asp:DropDownList>
<asp:LinqDataSource ID="LinqDataSource1" runat="server"
ContextTypeName="DataContext1" TableName="Table"
Where="DateField >= #DateField">
<WhereParameters>
<asp:Parameter DefaultValue="DateTime.Now" Name="DateField"
Type="DateTime" />
</WhereParameters>
</asp:LinqDataSource>
I'm getting a format exception saying that "The string was not recognized as a valid DateTime" when I try to run it. However, the dates in my database seem to be fine, because a DateTime.Parse works perfectly on them. The DateField is of type datetime in SQL.
What am I missing here?
Thanks!
The DefaultValue was what was wrong with the code as was suggested by the others.
However, setting the DefaultValue to
"<%# DateTime.Now %>"
like Andomar suggested (which would make the markup look something like this :
<WhereParameters>
<asp:Parameter DefaultValue="<%# DateTime.Now %>" Name="DateField" Type="DateTime" />
</WhereParameters>
will not work either because DataBinding expressions are only supported on objects that have a DataBinding Event, and neither Parameter or ControlParameter have one.
For a String, it's fairly easy to create a TextBox or Label and put the <%# %> expression in the value of that new field (more details here), but it was a bit more complicated with a DateTime value, as comparing an SQL DateTime with a .NET DateTime caused an exception.
It can be done quite easily in the Page_Load event by using
DataContext DataContext1 = new DataContext();
var c = from a in DataContext1.Field
where a.DateField >= DateTime.Now
select a;
DropDownList.DataSource = c;
DropDownList.DataBind();
I suspect it is failing on the DefaultValue.
Try:
DefaultValue="<%# DateTime.Now %>"