I keep getting a bad_any_cast exception when I retrieve data from a map.

Basically:

class DataType {
//protected:
public:
    boost::any value_;

    DataType(){};

    template <class type>
    DataType(type& value) : value_(value) {};

    template <class type>
    DataType(const type& value) : value_(value) {};

    // Provide constant & non constant version of operator =
    template <class type>
    type& operator=(type &rhs) {
        value_=rhs;
        return rhs;
    };

    template <typename type>
    const type& operator= (const type& rhs) {
        value_=rhs;
        return rhs;
    };
}

map <std::string, DataType> m;
DataType dt;

dt=3.5;

m["Data 1"] = dt;

DataType dt = fieldData["Data 1"];
fValue = boost::any_cast<float>(dt.value_); //returns a bad_any_cast

What am I doing wrong?

Joe McCay