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C# Cannot Unbox

defaultValue : decimal.Parse(_regKey.GetValue(keyName).ToString());

} Friday, July 20, 2007 8:32 PM 0 Sign in to vote As you own code clearly demostrates, there is no one way to convert the return value The boxing and Unboxing type of variable must be the same. My read code is a function that has an object as a parameter. –Jürgen Steinblock Jul 20 '09 at 13:56 add a comment| 4 Answers 4 active oldest votes up vote as if 1st time if youbox it in float, nextyou can notunbox that to double or vice versa. navigate here

defaultValue : _regKey.GetValue(keyName);

} public bool GetSetting(string formName, string keyName, bool defaultValue)

{ _regKey = Registry.CurrentUser.CreateSubKey(GetKeyName(formName));

return _regKey.GetValue(keyName) == null ? object o = i; The object o can then be unboxed and assigned to integer variable i: C# Copy o = 123; i = (int)o; // unboxing The following examples illustrate Boxing and Unboxing (C# Programming Guide) Visual Studio 2015 Other Versions Visual Studio 2013 Visual Studio 2012 Visual Studio 2010 Visual Studio 2008 Visual Studio 2005 Visual Studio .NET 2003  Updated: The language specification is the definitive source for C# syntax and usage.Related SectionsFor more information:Reference TypesValue TypesC# Language SpecificationFor more information, see the C# Language Specification.

Reply SGWellens All-Star 124309 Points 10172 Posts Moderator Re: why double first, before casting to a Float? So to fix this error make sure that the type matches before attempting to unbox: object thirdTest = Convert.ToInt16(0); short thirdtest2 = (short)thirdTest; share|improve this answer answered Jan 7 '12 at Since stucts/classes look the same to someone using them in code and could conceivably change, structs are inherently bad. Consider this code: Dim x As Integer = 5 Dim y As Object = x Dim z As Decimal = CType(y, Decimal) No error from compiler or at runtime.

Determine maximum frequency of input signal to make system LTI Why didn’t Japan attack the West Coast of the United States during World War II? If you just know the object can be converted to decimal in some way, try System.Convert.ToDecimal method. So for learning Angular and node module I have looked for many trainers in the market and attended their demos session but finally I have attended Shailendra demo class and i object thirdTest = Convert.ToInt16(0); int thirdtest2 = (int)thirdTest; // It blows up on this line. } The specific error that I get at runtime is Specified cast is not valid.

Is there a chance you boxed it, or the DB is boxing, to a different value type? –keyboardP Aug 5 '13 at 15:53 1 u better put that as an If you expecting a double then MAKE sure by validation that the source gives you a dobule. int? http://stackoverflow.com/questions/1085097/why-cant-i-unbox-an-int-as-a-decimal Being an author, Dot Net Tricks MEAN Stack Development Training is career turning point.

Browse other questions tagged c# unboxing or ask your own question. Pro How 5 Companies Maintain Optimal .NET Performance Pro Top 5 .NET Metrics, Tips & Tricks Boxing and unboxing in C# 10 Ways to Boost COBOL Application Development Boxing and unboxing float F2; F2 = (float)Convert.ToDouble(ds.Tables[0].Rows[i]["Forecast"]);. i'm feeling proud while writhing this testimonial.

This threw me for a loop. –Darryl Sep 24 '09 at 19:18 But if the value is sometimes a full number but other times a true decimal. https://msdn.microsoft.com/en-us/library/yz2be5wk.aspx Unboxing Explicit conversion of same reference type (which is being created by boxing process); back to a value type is known as unboxing. The error: Cannot unbox 'regKey.GetValue(keyName)' as a 'T' Here is the call: bool returnValue = GetSetting("somePath", "test", false)

Here is the function itself: public T GetSetting(string formName, string keyName, T defaultValue)

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They look the same, but they work very differently: http://blogs.msdn.com/ericlippert/archive/2009/03/19/representation-and-identity.aspx Reply SGWellens All-Star 124309 Points 10172 Posts Moderator Re: why double first, before casting to a Float? Boxing is an implicit conversion of a value type to the type object or to any interface type implemented by this value type. Thanks Dot Net Tricks for teaching me in depth practical concept. I would like to have feedback from my blog readers.

Let me explain you little more about Value and Reference Types. Reference Types Reference Types are different from value types in such a way that memory is allocated to them from the heap. This is not an uncommon problem, either: if you are using, for example, a SqlDataReader that contains a SMALLINT column, you cannot do: int x = (int)rdr["SmallIntColumn"]; Either of the following his comment is here This one-step, nested cast also worked.

Sign In·ViewThread·Permalink Boxing same as casting in C? object o = i; The result of this statement is creating an object reference o, on the stack, that references a value of the type int, on the heap. The thing to realize is that there is a difference between casting and unboxing.

MS Connect issue Aug 05, 2009 05:42 PM|RichardD|LINK smcirish Why did they close the MS Connect issue?

Saturday, March 17, 2007 5:02 AM 1 Sign in to vote Why don't you ToString() the output so it is the form of "False" or "false" or whatever and then use I'm not sure what you mean by that. Unboxing is an explicit conversion from the type object to a value type or from an interface type to a value type that implements the interface. Worked fine for me.

Sign in using Search within: Articles Quick Answers Messages home articles Chapters and Sections> Search Latest Articles Latest Tips/Tricks Top Articles Beginner Articles Technical Blogs Posting/Update Guidelines Article Help Forum Article Thanks Dot Net Tricks and Shailendra Sir. Then, the value stored in the variable i is changed from 123 to 456. The above example first boxs Int32 variable to an object type and than simply unbox it to x again.

The C# standard isn't quite right: Paul Linton If the source operand is a reference to an incompatible object, a System.InvalidCastException is thrown.

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