c# - mvc - html checkboxfor cannot implicitly convert type bool ?' to bool




cannot implicitly convert type 'bool?' to 'bool'. An explicit conversion exists(are you missing a cast?) (5)

bool? is not a bool. It is in reality a Nullable<bool> http://msdn.microsoft.com/en-us/library/b3h38hb0(v=vs.110).aspx

If you need the bool value then you should either cast like you are doing or call the .Value property on the bool?. There is also a .HasValue property you can check to make sure that it is not null.

If IsChecked is null, this line will error.

obj.IsDisplay = (bool) chkDisplay.IsChecked;

Error : cannot implicitly convert type 'bool?' to 'bool'. An explicit conversion exists (are you missing a cast?)

Code :

Test obj = new Test();
obj.IsDisplay = chkDisplay.IsChecked;

but when i use this means cast in bool then there is no error.

Test obj = new Test();
obj.IsDisplay = (bool) chkDisplay.IsChecked;

I need to know that, why need to cast this bool to bool.

Thanks


chkDisplay.IsChecked is of type bool?. Which means it can hold values true, false and null. However, obj.IsDisplay is of type bool. Which means it can only hold true or false.

Hence you have to explicitly cast it to type bool. However, this will still throw an exception if, the value you are trying to cast to bool is null.

bool? nullableBool = null;
bool notNullableBool = (bool)nullableBool; //This will throw InvalidOperationException

I'm facing your question when I'm using the null check operator ?.:

if (!RolesList?.Any()) //Not accepted: cannot convert bool? to bool

So I'm using this instead

if (RolesList?.Any() != true)
  //value is null or false

In your case you should set it like so:

obj.IsDisplay = chkDisplay.IsChecked ?? false;

You can use below code

obj.IsDisplay = chkDisplay.IsChecked == true?true:false;

bool is not equals bool?

bool can take two values, true and false

bool? can take three, true false and null

That is why they are different





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