I would like to save/update my changes in db with reflection. I just have name of a table and the id pk of the field. I try to update this table with reflection...
var table =(IQueryable)dbContext.ctx
.GetType()
.GetProperty(tableName)
.GetValue(dbContext.ctx, null);
First I have the table and with the Iqueryable I don't know how I can update my table in db.
Any help?
Thx
This answer is for a completeness of what you should do. Using Set (non-generic version) is the right approach. I know you just know the tableName (even the Type of your entity is not known). But Set requires a Type. So you need to find that type based on the PropertyType of the PropertyInfo you obtained from tableName. After obtaining a DbSet (non-generic), you can use all its methods without any more reflection. The entity passed in will be just object. Here is the detailed code:
//we don't check if tableName can be resolved successfully for simplicity
//NOTE that there should be only one generic argument
//We know it's a DbSet<T>, with this we should have T
var entityType = dbContext.ctx.GetType().GetProperty(tableName)
.PropertyType.GetGenericArguments()[0];
//now obtain an instance of DbSet normally
var entities = dbContext.ctx.Set(entityType);
//all methods of DbSet are available now although the arguments are
//object (not strongly typed).
Don't you need the DbSet<TEntity>?
var dbSet = (IDbSet<SomeEntity>)dbContext
.GetType()
.GetProperty(tableName, BindingFlags.Public | BindingFlags.Instance)
.GetValue(dbContext, null);
Now call DbSet<TEntity> methods as you would do it in a regular scenario, since you've a typed DbSet<T>.
A queryable won't help you much because as you've already guessed, it's about querying rather than performing write operations back to the database.
I can't use DbSet because I never know the entity, I ve juste the name of the table. I make an back office for change value of reference table, an generic interface..
Then, your solution is going with reflection even to add the entities to the DbSet<TEntity>:
object dbSet = dbContext
.GetType()
.GetProperty(tableName, BindingFlags.Public | BindingFlags.Instance)
.GetValue(dbContext, null);
dbSet.GetMethod("Add", BindingFlags.Public | BindingFlags.Instance)
.Invoke(new object[] { someEntityTypedAsObject });
Or you can store the DbSet<TEntity> as a dynamically-typed reference. This way, you can call it without reflection. It's a performance and readability gain:
dynamic dbSet = dbContext
.GetType()
.GetProperty(tableName, BindingFlags.Public | BindingFlags.Instance)
.GetValue(dbContext, null);
dbSet.Add(someEntity);
dynamic part ;)You shouldn't use GetProperty here, because context can contain entity sets, which were created using Set/Set<T> methods (thus, without any properties declared within context type).
The second, assuming, that entity types are unknown statically, you need to cast the result of non-generic Set call to non-generic DbSet type, and call its Add/Remove/etc methods.
