CODEWITHSUNDEEP
c#sql-serverchar
user1108948
user1108948

Reputation:

char cast vs Convert.ToChar()

I have a char type column in table. I want to convert it to a char in C#. It is working by 

char gender = Convert.ToChar(dataRow["Gender"]);

But it failed

 char gender = (char)(dataRow["Gender"]);

If a column is int type. I can use (int) to cast an object. Why it failed on char(exception)?

InValidCastException.

Thanks,

Upvotes: 3

Views: 8735

Answers (5)

Steve
Steve

Reputation: 216313

The datarow[column] is an expression of type 'object'

The Convert.ToChar() method has an overload that takes an object as argument, so the compiler knows what to do.

The (char)dataRow[column] is an explicit cast of dataRow[column] to the char type, but an automatic conversion from object to char doesn't exist

Upvotes: 3

Hans Kesting
Hans Kesting

Reputation: 39329

Apparently dataRow["Gender"]) contains an int value. This means it's a "boxed" int (an 'int' stored as an object). You can only cast that to a "real" int, you can't directly convert it to something else, like a char.

You can however use a two-step approach:

char gender = (char)(int)dataRow["Gender"];
  • first cast the boxed int ro a real one
  • then convert that int to a char.

Upvotes: 2

Jeppe Stig Nielsen
Jeppe Stig Nielsen

Reputation: 61992

If dataRow["Gender"] is in fact a (strongly typed) string, you could use

char g = dataRow["Gender"][0];

to get the zeroth character of that string (would fail if the string was null or empty). If, on the other hand, dataRow["Gender"] is a string but is typed as System.Object, you could use

char g = ((string)dataRow["Gender"])[0];

Upvotes: 0

Tigran
Tigran

Reputation: 62276

Most probabbly the real value in the cell is of type object. In this case you will get InvalidCastException.

Convert.ToChar works, instead, cause there is an overload that accepts object type.

Upvotes: 0

John Arlen
John Arlen

Reputation: 6699

Convert.ToChar reads the text value "A" and converts it into a character object with the value "A".

Casting assumes the original value IS a character object. The error tells you it is not.

Upvotes: 1

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