Entity Framework 6 .add() with variable table and column name - asp.net

Question

I am able to get a somewhat dynamic Entity Framework search result with the following simplified example, which pulls a single result from the DB or Cache:
string strTableName = "TableName2"
string strColumnName = "MyColumnName"
int intPrimaryKey = 1
Type returnType;
returnType = typeof(TableName1);
string queryResults = null;
switch (strTableName)
{
case "TableName2":
returnType = typeof(TableName2);
break;
}
var refColumnName = returnType.GetProperty(strColumnName );
var query = mydbEntity.Set(returnType).Find(intPrimaryKey );
var queryResults = refColumnName.GetValue(query).ToString();
This can also be adapted for Updating a record:
DataQuery.LeadsEntity.Entry(query).Property(strColumnName ).CurrentValue = "Whatever";
DataQuery.LeadsEntity.SaveChanges();
Is there an equivalent for way for .set(returnType).Add()? I'm not sure if there is a way to do this type of thinking using variable table and column names:
DataQuery.LeadsEntity.Set(returnType).Add(new returnType { PrimayKeyName = 1, refColumnName = "Something" });

Answer 1

If you don't know a priori what's the name of the primary key property, it could be a little painful to get it from the type.
This is the way I found more reliable to retrieve the primary key from the entity type:
private string[] GetKeyNames(DbContext context, Type entityType)
{
ObjectContext objectContext = ((IObjectContextAdapter)context).ObjectContext;
//create method CreateObjectSet with the generic parameter of the base-type
MethodInfo method = typeof(ObjectContext).GetMethod("CreateObjectSet", Type.EmptyTypes)
.MakeGenericMethod(entityType);
dynamic objectSet = method.Invoke(objectContext, null);
IEnumerable<dynamic> keyMembers = objectSet.EntitySet.ElementType.KeyMembers;
string[] keyNames = keyMembers.Select(k => (string)k.Name).ToArray();
_keyNamesCache[entityType] = keyNames;
return keyNames;
}
But assuming your primary keys are always a single property, you could use reflection to create the entity object and set its properties like this:
private void CreateEntity(Type entityType, object pkValue, Dictionary<string, object> Columns)
{
// Create the new entity
var entity = Activator.CreateInstance(entityType);
// Get the primary key property name
var pkName = GetKeyNames(context, entityType).First();
// Set Pk value
entityType.GetProperty(pkName).SetValue(entity, pkValue);
// Set other column(s)
foreach (var col in Columns)
{
entityType.GetProperty(col.Key).SetValue(entity, col.Value);
}
// Add the entity to the DbSet
using (var context = new YourContext())
{
context.Set(entityType).Add(entity);
}
}