CODEWITHSUNDEEP
c#
Alan2
Alan2

Reputation: 24572

Setting the value of a variable to null or to another value

I am trying to set the value of sequence to null if it's null or to a value 

 var sequence = parameters[11].Value != DBNull.Value ? 
                (int)parameters[11].Value : null;

But getting this message:

Error CS0173 Type of conditional expression cannot be determined because there is no implicit conversion between 'int' and ''

Can anyone give me advice on this one? Note that I need the (int) cast as the parameters are returned as objects.

Upvotes: 1

Views: 422

Answers (5)

Moumit
Moumit

Reputation: 9530

I don't know why nobody used default keyword .. it is very important and powerful key in c#.. you better start use of it .. in some critical generic situation .. it will play very vital role for you..

 var sequence = parameters[11].Value != DBNull.Value ? Convert.ToInt32(parameters[11].Value) : default(int?);

Upvotes: 0

Ian
Ian

Reputation: 30813

You may want to change the direct casting to the Convert.ToInt32

 int? sequence = parameters[11].Value != DBNull.Value ? 
    new Nullable<int>(Convert.ToInt32(parameters[11].Value.ToString())) : null;

Also, since you want to assign either int or null, then the data type must be nullable (i.e. int?)

Upvotes: 3

user1023602
user1023602

Reputation:

There are two problems: you have not declared the variable's type, and the compiler cannot work it out for itself.

int? sequence = (parameters[11].Value != DBNull.Value
                    ? (int)parameters[11].Value
                    : null);

This will compile ok, because the compiler can convert both int and null to Nullable<int>

Upvotes: 1

チーズパン
チーズパン

Reputation: 2778

You are casting your parameters[11].Value to int which does not seem to match the type of parameters[11].Value which you are setting.

Try to omit the (int).

Upvotes: 1

Byyo
Byyo

Reputation: 2243

assuming that var sequence is type of int? you can do

int? sequence = parameters[11].Value != DBNull.Value ? (int?)parameters[11].Value : null;

Upvotes: 4

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