public static Expression PrepareExpressionFromAnonymous <TSource>(Expression sourceExpression, Expression <Func <TSource, object> > expression)
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
// Anonymous initializations are not implemented as member initialization but as plain constructor call.
var newExpression = expression.Body as NewExpression ??
throw new ArgumentException("The expression must be an anonymous initialization, e.g. x => new { Name = x.Name, Age = x.Age + 5 }");
var instance = new DmlExpressionRewriter(expression.Parameters);
instance.AddSettersFromAnonymousConstructor(newExpression, "");
return(PrepareExpression <TSource>(sourceExpression, instance._assignments));
}
public static Expression PrepareExpression <TSource, TTarget>(Expression sourceExpression, Expression <Func <TSource, TTarget> > expression)
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
var memberInitExpression = expression.Body as MemberInitExpression ??
throw new ArgumentException("The expression must be a member initialization, e.g. x => new Dog { Name = x.Name, Age = x.Age + 5 }, " +
// If someone call InsertSyntax<TSource>.As(source => new {...}), the code will fail here, so we have to hint at how to correctly
// use anonymous initialization too.
"or an anonymous initialization with an explicitly specified target type when inserting");
if (memberInitExpression.Type != typeof(TTarget))
{
throw new TypeMismatchException($"Expecting an expression of exact type {typeof(TTarget).AssemblyQualifiedName} " +
$"but got {memberInitExpression.Type.AssemblyQualifiedName}");
}
var instance = new DmlExpressionRewriter(expression.Parameters);
instance.AddSettersFromBindings(memberInitExpression.Bindings, "");
return(PrepareExpression <TSource>(sourceExpression, instance._assignments));
}
/// <summary> /// Perform an <c>update versioned</c> on the entities. The update operation is performed in the database without reading the entities out of it. /// </summary> /// <returns>The number of updated entities.</returns> public int UpdateVersioned() => _source.ExecuteUpdate(DmlExpressionRewriter.PrepareExpression <TSource>(_source.Expression, _assignments.List), true);