ArgumentException: value cannot be null, parameter name : key

[msjonathan]

Hej hej,

I have a list of my own object PossibleField like this.

private List<PossibleField> PossibleFields {get; set; }

Then I add some objects to the PossfibleFields with the .Add(....) function
And if I do a count, all the object are in the list.
Then I want tot do a foreach of all the possiblefield's.

foreach(PossibleField field in PossibleFields)
{
}

But the compiler says the following: value cannot be null, parameter name: key.

The same code worked before. Not only with the foreach, also with FirstOrDefault, Find, .... All the functions that retrieve something of the list.

Does anybody has any idea? I'am willing to try everything :D
Greetz,

Jonathan

[msjonathan]

it was no problem at the list, it was the line above that caused the problem :D

Greetz,

Jonathan