Explicit casting with Type variable

[Kaikus]

Is it possible to make a explicit casting using a variable? I'm passig a boxed object, and it's Type, as arguments. Inside the method I would like to unbox and use the content private void myMethod ( Object boxedObject, Type dataType) { .... ... = (dataType)boxedObject; .... } I know it doesn't compile this way. By the moment i'm using this kind of code: switch (dataType.ToString()) { case "int": ... = (int)boxedObject; case "string" ... = (string)boxedObject; ... } But... is there a way to make something similar to "(dataType)boxedObjec)" that doesn't need using 'if' or 'case' for every dataType? Thanks!

[OriginalGriff]

You can probably do it via reflection, but what are you going to do with it then? If (for example) "as" worked that way, so you could do " = boxedObject as dataType;" what are you going to assign it to? Other than another object? You can't pass it to another method, because any type you haven't covered will either no compile or will throw an exception. You can't use it's properties, as you can't be sure it has those properties (other than ToString and the other really basic ones). What are you trying to do, that you need this?

All those who believe in psycho kinesis, raise my hand. My :badger:'s gonna unleash hell on your ass. :badger:tastic!

[Kaikus]

'as' works the same way than normal casting... Doesn't work... :( What I want is compare the given value with data values from a dataset. So I first get the needed column DataType, and then I compare whith the properly unboxed value. The basic code would be: public int SeekRow (string colName, object value) { Type dataType = myDataSet.MyTable.Columns[colName].DataType; for (row=0; ...) { if (myDataSet.myTable[row][ColName]==(dataType)value) { return row; } } return -1; } If I can't, I must use a lot of untidy 'if' ot 'case'...

[OriginalGriff]

I know "as" doesn't work - that's why I said 'If (for example) "as" worked that way' rather than 'Use "as" - it will do what you want' I can't help thinking you are overdoing this a little, but... Do you really need to know what the datatype is? Since your are returning only the row number rather than the value, either compare it directly

myDataSet.myTable[row][ColName] == value

or use ToString and compare that way.

myDataSet.myTable[row][ColName].ToString() == value.ToString()

Otherwise you have to be sure that all the objects you may pass the routine implement the == operator... I would still think about why I was doing this in this (rather odd) way in the first place.

All those who believe in psycho kinesis, raise my hand. My :badger:'s gonna unleash hell on your ass. :badger:tastic!

[Gideon Engelberth]

Assuming that you are not actually passing objects in, you might be able to use generics here:

public int SeekRow<T>(string colName, T value)
{
for (row = 0; ...)
{
if ((T)myDataSet.myTable[row][ColName] == value)
{
return row;
}
}
return -1;
}

int row1 = SeekRow("Age", 25); //calls SeekRow<int>
int row2 = SeekRow("Name", "John Doe"); //calls SeekRow<string>

[PIEBALDconsult]

System.Convert.ChangeType ? The only useful member of Convert.

[Kaikus]

This is the temporal solution I have implemented, converting ToString. As you say, otherwise I should be sure to implement "==" operator for every object. Thanks for your reply!

[Kaikus]

Nice! I didn't know that. Just becouse I am returning to c# programmin after... 6 years without programming at all!! And I have only installed .NET Framework 1, do I wasn't aware of Generics. I will try! Thanks!

[Gideon Engelberth]

If you want to use generics, you will need at least .NET 2.0 (might as well just get 3.5 since it's the newest and contains 2.0)