/// <summary>
/// Loads query method expression from <see cref="ExpressionQueryMethod"/> member.
/// </summary>
/// <param name="parentType">Type of object that declares association</param>
/// <param name="objectType">Type of object associated with query method expression</param>
/// <returns><c>null</c> of association has no custom query method expression or query method expression, specified
/// by <see cref="ExpressionQueryMethod"/> member.</returns>
public LambdaExpression?GetQueryMethod(Type parentType, Type objectType)
{
if (ExpressionQuery == null && ExpressionQueryMethod.IsNullOrEmpty())
{
return(null);
}
Expression queryExpression;
var type = MemberInfo.DeclaringType;
if (type == null)
{
throw new ArgumentException($"Member '{MemberInfo.Name}' has no declaring type");
}
if (!ExpressionQueryMethod.IsNullOrEmpty())
{
queryExpression = type.GetExpressionFromExpressionMember <Expression>(ExpressionQueryMethod);
}
else
{
queryExpression = ExpressionQuery !;
}
var lambda = queryExpression as LambdaExpression;
if (lambda == null || lambda.Parameters.Count != 2)
{
if (!string.IsNullOrEmpty(ExpressionQueryMethod))
{
throw new LinqToDBException(
$"Invalid predicate expression in {type.Name}.{ExpressionQueryMethod}. Expected: Expression<Func<{parentType.Name}, IDataContext, IQueryable<{objectType.Name}>>>");
}
else
{
throw new LinqToDBException(
$"Invalid predicate expression in {type.Name}. Expected: Expression<Func<{parentType.Name}, IDataContext, IQueryable<{objectType.Name}>>>");
}
}
if (!lambda.Parameters[0].Type.IsSameOrParentOf(parentType))
{
throw new LinqToDBException($"First parameter of expression predicate should be '{parentType.Name}'");
}
if (typeof(IDataContext) != lambda.Parameters[1].Type)
{
throw new LinqToDBException("Second parameter of expression predicate should be 'IDataContext'");
}
if (!(typeof(IQueryable <>).IsSameOrParentOf(lambda.ReturnType) &&
lambda.ReturnType.GetGenericArguments()[0].IsSameOrParentOf(objectType)))
{
throw new LinqToDBException("Result type of expression predicate should be 'IQueryable<{objectType.Name}>'");
}
return(lambda);
}
public bool HasQueryMethod()
{
return(ExpressionQuery != null || !ExpressionQueryMethod.IsNullOrEmpty());
}
/// <summary>
/// Loads query method expression from <see cref="ExpressionQueryMethod"/> member.
/// </summary>
/// <param name="parentType">Type of object that declares association</param>
/// <param name="objectType">Type of object associated with query method expression</param>
/// <returns><c>null</c> of association has no custom query method expression or query method expression, specified
/// by <see cref="ExpressionQueryMethod"/> member.</returns>
public LambdaExpression GetQueryMethod(Type parentType, Type objectType)
{
if (ExpressionQuery == null && ExpressionQueryMethod.IsNullOrEmpty())
{
return(null);
}
Expression queryExpression = null;
var type = MemberInfo.DeclaringType;
if (type == null)
{
throw new ArgumentException($"Member '{MemberInfo.Name}' has no declaring type");
}
if (!string.IsNullOrEmpty(ExpressionQueryMethod))
{
var members = type.GetStaticMembersEx(ExpressionQueryMethod);
if (members.Length == 0)
{
throw new LinqToDBException($"Static member '{ExpressionQueryMethod}' for type '{type.Name}' not found");
}
if (members.Length > 1)
{
throw new LinqToDBException($"Ambiguous members '{ExpressionQueryMethod}' for type '{type.Name}' has been found");
}
var propInfo = members[0] as PropertyInfo;
if (propInfo != null)
{
var value = propInfo.GetValue(null, null);
if (value == null)
{
return(null);
}
queryExpression = value as Expression;
if (queryExpression == null)
{
throw new LinqToDBException($"Property '{ExpressionQueryMethod}' for type '{type.Name}' should return expression");
}
}
else
{
var method = members[0] as MethodInfo;
if (method != null)
{
if (method.GetParameters().Length > 0)
{
throw new LinqToDBException($"Method '{ExpressionQueryMethod}' for type '{type.Name}' should have no parameters");
}
var value = method.Invoke(null, Array <object> .Empty);
if (value == null)
{
return(null);
}
queryExpression = value as Expression;
if (queryExpression == null)
{
throw new LinqToDBException($"Method '{ExpressionQueryMethod}' for type '{type.Name}' should return expression");
}
}
}
if (queryExpression == null)
{
throw new LinqToDBException(
$"Member '{ExpressionQueryMethod}' for type '{type.Name}' should be static property or method");
}
}
else
{
queryExpression = ExpressionQuery;
}
var lambda = queryExpression as LambdaExpression;
if (lambda == null || lambda.Parameters.Count != 2)
{
if (!string.IsNullOrEmpty(ExpressionQueryMethod))
{
throw new LinqToDBException(
$"Invalid predicate expression in {type.Name}.{ExpressionQueryMethod}. Expected: Expression<Func<{parentType.Name}, IDataContext, IQueryable<{objectType.Name}>>>");
}
else
{
throw new LinqToDBException(
$"Invalid predicate expression in {type.Name}. Expected: Expression<Func<{parentType.Name}, IDataContext, IQueryable<{objectType.Name}>>>");
}
}
if (!lambda.Parameters[0].Type.IsSameOrParentOf(parentType))
{
throw new LinqToDBException($"First parameter of expression predicate should be '{parentType.Name}'");
}
if (typeof(IDataContext) != lambda.Parameters[1].Type)
{
throw new LinqToDBException("Second parameter of expression predicate should be 'IDataContext'");
}
if (!(typeof(IQueryable <>).IsSameOrParentOf(lambda.ReturnType) &&
lambda.ReturnType.GetGenericArguments()[0].IsSameOrParentOf(objectType)))
{
throw new LinqToDBException("Result type of expression predicate should be 'IQueryable<{objectType.Name}>'");
}
return(lambda);
}
