Expression of type 'System.Linq.Expressions.Expression cannot be used for parameter of type

Because string is not a delegate type, Entity Framework cannot convert lambda expressions to it.

In the C# code I use, Entity Framework is used. I'm having an unexpected odd experience and am seeking for solutions....Projects for Cases 1, 2, 3, and 4... RivWorks.dll... RivWorks.Service.dll... RivWorks.Alpha.dll ...Samples (all of them are effective):...RivWorks.Alpha.dll:...public static bool EndNegotitation(long ProductID) { var produ...

"A statement body lambda expression cannot be transformed to an expression tree."

Is ...objects... a context for a Linq-To-SQL database? In such situation, the only valid expressions to the right of the => operator are straightforward ones. The reason is because instead of being performed, these expressions are translated to SQL and then used to query the database. Try it....Arr[] myArray = objects.Select(o => new Obj() { V...

"LINQ to Entities does not support the LINQ expression node type 'Invoke'" - perplexed!

I'm attempting to send an anonymous function into my EF later so it can be utilized in my Linq query. The procedure would take an INT as input and output a BOOL (u.RelationTypeId is an INT). A condensed description of my role is given below:...public IEnumerable<UserBandRelation> GetBandRelationsByUser(Func<int, bool> relation) { using (var ctx...

The ArrayIndex LINQ expression node type is not supported in LINQ to Entities.

public List<string> GetpathsById(List<long> id) { long[] aa = id.ToArray(); long x; List<string> paths = new List<string>(); for (int i = 0; i < id.Count; i++) { x = id[i]; Presentation press = context.Presentations.Where(m => m.PresId == aa[i]).FirstOrDefault(); paths.Add(press.FilePath); } r...

The LINQ expression node type 'Invoke' is not supported in the entity framework's LINQ to Entities.

The AsExpandable() function created by Joe Albahari and included in LINQKIT may be used to remedy this issue. He is the same person behind...PredicateBuilder... thing you're utilizing, I see....If querying with Entity Framework, change the last line to this:...return objectContext.Products.AsExpandable().Where(predicate);...You may download the LIN...

Complex mappings are used to translate an expression tree from one type to another.

influenced by zzzz-5 zzzz I'm attempting to translate a model class attribute to an expression based on the real object. The two classes in question are as follows:...public class Customer { public string FirstName { get; set; } public string LastName { get; set; } public int Id { get; set; } public DateTime? BirthDate { get; set; }...

System.InvalidCastException: Unable to cast object of type 'System.Int32' to type 'System.String'

The exception message indicates that your Customer class resembles this....public class Customer { [StringLength(4)] public int CustomerID { get; set;} } ...Note that you are unable to use...StringLength... on an...int... property....Eliminate the...StringLength... and there should be no more validation exceptions.

Operator '&&' cannot be applied to operands of type 'lambda expression' and 'lambda expression

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Pass expression parameter as argument to another expression

I have a search that limits the results:...public IEnumerable<FilteredViewModel> GetFilteredQuotes() { return _context.Context.Quotes.Select(q => new FilteredViewModel { Quote = q, QuoteProductImages = q.QuoteProducts.SelectMany(qp => qp.QuoteProductImages.Where(qpi => q.User.Id == qpi.ItemOrder)) }); } ...I'm using the ...

Unable to cast object of type 'System.Linq.Expressions.MethodCallExpression' to type 'System.Linq.Expressions.LambdaExpression'

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