How to convert a string type to a money type or how to typecast a string type to money type in C# in crm2011?

Hi

I want to convert a string type to money type in crm2011.Is it possible? Is there any alternative way to handle this?

I am using the following piece of code and it is throwing error.It says cannot convert string type to money type..

mny =((CrmSdk.Money)objCol.txt1).Value;

Thanks..

Dibyasingh Tripathy