C# - Get ADO.NET Entity To Generate 1:1 Navigation Properties?
Jan 29, 2010Is there a way to get ADO.NET Entity to generate 1:1 navigation properties? If I do foreign keys I always get 1:N navigation properties.
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Implementing Navigation Properties In Entity Framework?
Oct 1, 2010I've been learning MVC 2 and I have pretty much everything understood except for the model part of things, I understand what the model is but actually implementing it has me confused.
Here's my situation, I have my DB which has 3 tables;
Ideas - table of ideas
Tags - table of tags
IdeaTag - link table connecting the above 2 tables via FKs
So when using the Entity Framework (.edmx) designer in VS2010 I get 2 classes created in the Designer, which obviously map to my DB tables and Navigation Properties in Idea for Tags & Idea for Tag.
So this is all fine until I actually try to add tags to an idea, what's the best practise for dealing with Navigation Properties? I wanted to add a Textbox which will then map to the Tags property in the Idea class but I'm unsure how I'd go about this.
Most of the MVC tutorials which discuss EF or Linq to SQL are quite basic.
ADO.NET :: Bind To Navigation Properties?
Aug 5, 2010I warking with EF 4 in vs 2010 with asp.net application.
In my page I put detailsview which connet to objectdatasource.
I want to bind navigate property to text in murkup like this:
<asp:TextBox
ID="txt_legalStatus"
runat="server"
Text='<%# Databinder.Eval(Container.DataItem,"legal_status_codes.Term")
%>'></asp:TextBox>
according to this article (from o'reilly book)
Using the Entity Framework in n-Tier ASP.NET Applications which write by julie lerman in section "Example 21.10. A TemplateField, which can be used for navigation properties".
When I run the application I get a Compilation Error "The name 'Databinder' does not exist in the current context" someone can tell me what my mistake?
EF1 Navigation Properties Not Working?
Nov 17, 2010My entity model was generated from the existing database. There is a many-to-many junction table picked up and hidden by EF.
The relationship is definitely working because this query returns 2 users as expected.
public IQueryable<User> FindUsersByGroupID(int group_id)
{
return db.Users.Where(u => u.Groups.Any(g => g.Group_ID == group_id));
}
But when locating a user that is part of the above result set the Groups navigation property count is 0. I shouldn't have to explicitly join.. right?
public User FindUserByID(int id)
{
return db.Users.First(u => u.User_ID == id);
}
ADO.NET :: Bind To Navigation Properties To Text
Aug 5, 2010I warking with EF 4 in vs 2010 with asp.net application. In my page I put detailsview which connet to objectdatasource. I want to bind navigate property to text in murkup like this:
<asp:TextBox
ID="txt_legalStatus"
runat="server"
Text='<%# DataBinder.Eval(Container.DataItem,"legal_status_codes.Term")
%>'></asp:TextBox>
according to
this article (from o'reilly book)
Using the Entity Framework in n-Tier ASP.NET Applications which write by julie lerman in section "Example 21.10. A TemplateField, which can be used for navigation properties". When I run the application I get a exception "The ObjectContext instance has been disposed and can no longer be used for operations that require a connection" someone can tell me what its not working?
Displaying Navigation Properties On A GridView Using EntityDataSource?
Apr 4, 2011I have an EntityDataSource I've mapped to the entity Resident which includes two navigation properties (Building1, Room1). I've set my GridView to use this EntityDataSource and set the EntityDataSource Include property to Building1, Room1 so it includes these navigation properties and have added these columns to the GridView. When I run the application instead of displaying the associated navigation property it shows this: webHousingAdmin.BuildingHow can I get it to display the actual value? Code looks like this for GridView:
<asp:TemplateField>
<ItemTemplate>
<asp:Label ID="lbl1" runat="server" Text='<%# Bind("Building1") %>' />
</ItemTemplate>
</asp:TemplateField>
I've gotten it to display the actual value by using the following code:
<asp:TemplateField HeaderText="Building">
<ItemTemplate>
<asp:Label ID="lblBuilding" Text='<%# Bind("Building1.building_name") %>' runat="server" />
</ItemTemplate>
</asp:TemplateField>
But is there a simpler way to do this? This only displays the text, doesn't let me edit it...if I can do it as a boundfield that would be ideal.
C# - Entity Framework - How To Use Navigation Property
Feb 2, 2011 I use EF 4 and C #.
I need populate a Pure Junction Table (containing only FK to other tables) when an EntityDataSource _Inserted event is raised.
I have 3 Tables in my Database:
[code]....
Here a useful resource:
But I am not able to implment it:
[code]....
Databinding Exception With Entity Navigation Property?
Mar 4, 2010I have two Entity classes: Order and OrderItem. Order contains a navigation property OrderItemSet of type
System.Data.Objects.DataClasses.EntityCollection<OrderItem>
On an aspx page is a FormView bound to this EntityDataSource:
[code]....
When I run the application I get an exception pointing to the line DataSource='<%# Eval("OrderItemSet")%>' in markup and telling me:
DataBinding: System.Web.UI.WebControls.EntityDataSourceWrapper does not contain a property with name 'OrderItemSet'
What is wrong here?
Visual Studio 2008 Generate Top Navigation Menu?
Dec 21, 2010I came across this site and like the top nav menu [URL] can visual studio 2008 generate such a menu like that. Moreover, what about if I want to apply security on what to show in the menu. For instance, I will have 3 departments ( Finance, Accounting and Marketing ) each department has its own apsx page. Depending on role, I need to show / not show a page under each department. How can I enforce such thing.
View 1 RepliesEntity Framework. Updating EntityCollection Using Disconnected Objects Via Navigation Property?
Apr 22, 2010I have a question, much liket this unanswered one. I'm trying to work with the entity framework, and having a tough time getting my foreign tables to update. I have something basically like this in the DB:
Incident (table):
-ID
-other fields
Responses (table):
-FK:Incident.ID
-other fields
And and entities that match:
Incident (entity)
-ID
-Other fields
-Responses (EntityCollection of Responses via navigation property)
Each Incident can have 0 or more responses.
In my Webpage, I have a form to allow the user to enter all the details of an Incident, including a list of responses. I can add everything to the database when a new Incident is created, however I'm having difficulty with editing the Incident.
When the page loads for edit, I populate the form and then store the responses in the viewstate. When the user changes the list of responses (adds one, deletes one or edits one). I store this back into the viewstate. Then when the user clicks the save button, I'd like to save the changes to the Incident and the Responses back to the DB. I cannot figure out how to get the responses from the detached viewstate into the Incident object so that they can be updated together.
Currently when the user clicks save, I'm getting the Incident to edit from the db, making changes to the Incident's fields and then saving it back to the DB. However I can't figure out how to have the detached list of responses from the viewstate attach to the Incident. I have tried the following without success:
Clearning the Incident.Responses collection and adding the ones from the viewstate back in:
Incident.Responses.Clear()
for each objResponse in Viewstate("Responses")
Incident.Responses.add(objResponse)
next
Creating an EntityCollection from my list and then assiging that to the Incident.Responses
Incident.Responses = EntityCollectionFromViewstateList
Iterating through the responses in Incident.Response and assigning the corresponding object from viewstate:
for each ObjResponse in Incident.Responses
objResponse = objCorrespondingModifedResonseFromViewState
Next
These all fail, I'd like to be able to merge the changes into the Inicdent object so that when the BLL calls SaveChanges on the changes to both the Incident and Responses will happen at the same time.
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Sep 28, 2010In an MVC view, I'm looking for a way to determine if a parent entity's collection of child entities is empty, so I can decide if I need to call a RenderPartial() or not.
For a one-to-one I've been using the following:
<% if (Model.Book.GenreReference.EntityKey != null) %>
{.....}
but I'm unsure how to do it in a one-to-many scenario, or if it can even be done without the use of Include() or Load().
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<cc1:CollapsiblePanelExtender
ID="CPExtender1"
...
CollapsedImage=" [path to image] "
...
/>
I do not know how to do it this way:
<cc1:CollapsiblePanelExtender
ID="CPExtender1"
...
CollapsedImage=" [method call] "
...
/>
I have tried this:
CollapsedImage="<%# Eval( Namespace.Class.GetHelpImage() ) %>"
That DataBinding does not return the path to the image using a method call so I test the GetHelpImage() method call and learn it does not return the path as text.
I know the path to the image is correct because I can paste the text into the CollapsiblePanelExtender CollapsedImage property and the control will find and display the collapsed image.
// this method call does not return the text for a path
// so I am not even doing this correctly either.
public static string GetHelpImage()
{
return "[known path to image]";
}
// Image to test getting text from GetHelpImage() method call
<asp:Label ID="TestGetImagePathLabel" runat="server"
Text="<%# Eval( GetHelpImage() ) %>"/>
I'm doing this all wrong. Where's a blogged example of how to populate the control using an expression?
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[code]....
Except r, my query result var, is always true no matter what data it receives. I have tried the sub query using other properties of tEventOption and get the same 'true' result each time. I know that the data does not reflect this result so I clearly have a problem with the structure of my query, but for the life of me I cannot find a way to resolve it.
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The problem is, that code
myBD my_bd = new myBD();
var articles = by_bd.Article;
works OK, I can see that an Author and an Article has 1 comment. But that code
var comm = (from u in my_bd.Comment
where ......
select u);
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I have twelve databases, each of them has the same structure and the same stored procedure.
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var firstList = from chartItem in db.ChartItems
join vote in db.Votes on chartItem.ixChartId equals vote.ixChartId into j1
where chartItem.ixChartId == id[code]...
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Votes Name
20 - ChartItemname
15 - ChartItemname
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I need to login (ok)
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i already handle the page load on the default page.
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