I have 2 classes with a LINQ association between them i.e.:
Table1: Table2:
ID ID
Name Description
ForiegnID
The association here is between Table1.ID -> Table2.ForiegnID
I need to be able to change the value of Table2.ForiegnID, however I can't and think it is because of the association (as when I remove it, it works).
Therefore, does anyone know how I can change the value of the associated field Table2.ForiegnID?
Check out the designer.cs file. This is the key's property
[Column(Storage="_ParentKey", DbType="Int")]
public System.Nullable<int> ParentKey
{
get
{
return this._ParentKey;
}
set
{
if ((this._ParentKey != value))
{
//This code is added by the association
if (this._Parent.HasLoadedOrAssignedValue)
{
throw new System.Data.Linq.ForeignKeyReferenceAlreadyHasValueException();
}
//This code is present regardless of association
this.OnParentKeyChanging(value);
this.SendPropertyChanging();
this._ParentKey = value;
this.SendPropertyChanged("ParentKey");
this.OnServiceAddrIDChanged();
}
}
}
And this is the associations property.
[Association(Name="Parent_Child", Storage="_Parent", ThisKey="ParentKey", IsForeignKey=true, DeleteRule="CASCADE")]
public Parent Parent
{
get
{
return this._Parent.Entity;
}
set
{
Parent previousValue = this._Parent.Entity;
if (((previousValue != value)
|| (this._Parent.HasLoadedOrAssignedValue == false)))
{
this.SendPropertyChanging();
if ((previousValue != null))
{
this._Parent.Entity = null;
previousValue.Exemptions.Remove(this);
}
this._Parent.Entity = value;
if ((value != null))
{
value.Exemptions.Add(this);
this._ParentKey = value.ParentKey;
}
else
{
this._ParentKey = default(Nullable<int>);
}
this.SendPropertyChanged("Parent");
}
}
}
It's best to assign changes through the association instead of the key. That way, you don't have to worry about whether the parent is loaded.
Table1: Table2:
ID ID
Name Description
ForeignID
With this :
Table2.ForeignID = 2
you receive an error..........
Example :
You can change ForeignID field in Table 2 whit this :
Table2 table = dataContext.Table2.single(d => d.ID == Id)
table.Table1 = dataContext.Table1.single(d => d.ID == newId);
Where the variable newId is the id of the record in Table 2 that would you like associate whit the record in Table 1
You wanna to associate with another record in table1 or change table1.id? if it's option 1, you need to remove that association and set a new one. If option 2, check you db and see if update cascade yes enabled for this fk and than get record and change value of id.
