Convert.ChangeType从int转换为bool

Question

Using the following to get values from query string and convert to specific types should there be a need.

public static T Convert<T>(NameValueCollection QueryString, string KeyName, T DefaultValue) where T : IConvertible
    {
        //Get the attribute
        string KeyValue = QueryString[KeyName];

        //Not exists?
        if (KeyValue == null) return DefaultValue;

        //Empty?
        if (KeyValue == "") return DefaultValue;

        //Convert
        try
        {
            return (T)System.Convert.ChangeType(KeyValue, typeof(T));
        }
        catch
        {
            return DefaultValue;
        }
    } 

A call would be made as such

int var1 = Convert<int>(HttpContext.Current.Request.QueryString,"ID", 0);

However when trying to do the following it does not work correctly so my question is, is it possible to change the code to handle bools if the value being retrieved from the querystring variable is a 1 or a 0 instead of a true of false.

ie... instead of
http://localhost/default.aspx?IncludeSubs=true
the call is
http://localhost/default.aspx?IncludeSubs=1

bool var1 = Convert<bool>(HttpContext.Current.Request.QueryString,"IncludeSubs", false);

Answer 1

You can modify your convert method in order to handle booleans as following:

//Convert
try
{
    var type = typeof(T);
    if(type == typeof(bool))
    {
        bool boolValue;
        if(bool.TryParse(KeyValue, out boolValue))
            return boolValue;
        else
        {
            int intValue;
            if(int.TryParse(KeyValue, out intValue))
                return System.Convert.ChangeType(intValue, type);
        }
    }
    else
    {
        return (T)System.Convert.ChangeType(KeyValue, type);
    }
}
catch
{
    return DefaultValue;
}

In this way you can convert to boolean values like: "true" , "False" , "0" , "1"