Deleting Entity With Child Relationships
Apr 10, 2010
EF is so frustrating. I can't seem to be able to get my head around what I need to do so I can delete an object. I seem to be able to remove the object but not the related child objects. Can anyone tell me what is the rule of thumb when you want to delete all related child objects of a given object? I've tried loading all related objects like this:
Entry entry = ModelContext.GetObjectByKey(new EntityKey("ModelContainer.EntrySet", "Id", id)) as Entry;
entry.ChildEnteries.Load();
if (entry != null)
{
ModelContext.DeleteObject(entry);
ModelContext.SaveChanges();
}
I get errors related to the relationships: A relationship is being added or deleted from an AssociationSet 'EntryEntry'. With cardinality constraints, a corresponding 'Entry1' must also be added or deleted. Why can't I just load the object using modelcontext.GetObjectByKey and remove it along with its child objects? My other question is can I delete an object using Entity command like so? DELETE e from objectset as e where e.id = 1 I've tried few variations and all of them throw exceptions.
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Feb 4, 2010
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[Code]....
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[Code]....
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Jan 24, 2011
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[Code]....
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[Code]....
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Aug 19, 2010
I have the next aspx page.
<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.Master" AutoEventWireup="true"
CodeBehind="newsEditor.aspx.cs" Inherits="ExpertSiteV2.newsEditor" %>[code]....
In some situation i want to delete all the contents of Panel1. I write in the code:
Panel1.Controls.Clear();
But it doesn't work and i get message: Page cannot be null. Please ensure that this operation is being performed in the context of an ASP.NET request.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.InvalidOperationException: Page cannot be null. Please ensure that this operation is being performed in
the context of an ASP.NET request.
Source Error:An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace: [InvalidOperationException: Page cannot be null. Please ensure that this operation is being performed in the context of an ASP.NET request.]
System.Web.UI.ScriptManager.get_IPage()
+373832 System.Web.UI.ScriptManager.OnPagePreRenderComplete(Object
sender, EventArgs e) +54
System.Web.UI.Page.OnPreRenderComplete(EventArgs
e) +8698462
System.Web.UI.Page.ProcessRequestMain(Boolean
includeStagesBeforeAsyncPoint, Boolean
includeStagesAfterAsyncPoint) +1029
Blockquote
What's wrong? Or how should i do this properly?
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Jul 9, 2010
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Apr 20, 2010
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i have completed this till to that , it retrieves all foreign keys but how to delete now on the base of priority.
[Code]....
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Mar 10, 2010
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Nov 25, 2010
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[code]....
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[Code]....
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Code below for convenience...
EDIT Wrapped a LinkButton around it because I have some jquery code in here as well which stops the page execution to wait for user confirmation. Pressing "ok" continues page execution.
<asp:LinkButton ID="oDeleteLink" CssClass="oDeleteIcon" CommandName="Delete" CommandArgument='<%# Eval("iAccountID") %>' runat="server">
<asp:ImageButton ImageUrl="/files/system/icons/trash-steel-16.png" ToolTip="Delete This Account" AlternateText="Delete" ID="oDeleteIcon" runat="server" />
</asp:LinkButton>
protected void oAccounts_ItemCommand(Object Sender, RepeaterCommandEventArgs e) {
if (e.CommandName == "Delete") {
int ID = e.CommandArgument.ToString().Numeric();
db.SPs.SpDeleteAccount(ID).Execute();
UI.Confirm(uiBroadcast, "Account has been deleted", "300px");
BindAccounts();
}
}
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Aug 5, 2010
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Nov 22, 2010
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Mar 16, 2011
this is a bit of a nomenclature question:what is the correct way to describe the relationships between these classes (the thing that throws me off is the use of generic types here):
[Code]....
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Using dataloadoptions i have tried the following example
[Code]....
Now i need to ask how can i display Category ID and Category Name of the productID (i am supposing that One product can be in at most one category) by extending the above example Regards.
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May 27, 2010
Say I have this entity with a lot of attributes. In the input form I have decided to implement a wizard control so I can collect information about this entity in several steps. The problem is that I need to collect information that has been modeled has many to many relationships. I am planning to use a telerik gridview to manage this (add/edit/delete), the problem is where do I store that data since the entity in a insert form is not created on the database yet. OK so I can store all that info in temporary lists residing in the viewstate, waiting for the final submit where I dump all that in the DB, but one of the steps I am collecting files...now storing files in the viewstate is out of the question, same as as storing them in the session...I have been thinking of implementing in a way that the user has to submit some info first (say first 3 steps), commit the data to the database creating the parent entity and then start inserting all the childs entities...but this will get weird as it's confusing since on the first steps you not saving the data to the DB and on the next ones you are commiting directly...
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Apr 21, 2010
Just a quick question for those more familiar with FluentNHibernate. I've read the quick start things, and the docs on their site, but am still a tad off. Are the following maps correct, in terms of the HasOne / HasMany relationships? If not, correct them, and give me reasons, so I better understand.
C sharp Code:
[code]....
These will eventually go into a convention file, but for now, I just need to know how to code relationships period.
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