C#

code block 

miss YY wrote:

set datetimepicker1 and datetimepicker2 modifiers to public on form1

miss YY wrote:

on form2 like this
Form1 frm = new Form1();

miss YY wrote:

Form1 frm=new Form1();
string from, to;
from = frm.dateTimePicker1.Value.ToString("yyyy-MM-dd");
to = frm.dateTimePicker2.Value.ToString("yyyy-MM-dd");

public static class Test
{
    public static T GenericDecodeData<T>(byte[] data, string encRules)
    {
        // ...
        return default(T);
    }

    public static Type GetDownloadType(int id)
    {
        switch (id)
        {
            case DOWNDIRECT: return typeof(DownDirect);
            case DOWNOTHER: return typeof(DownOther);
            case DOWNHEHE: return typeof(DownHehe);
            default: return null;
        }
    }
    public static object DecodeData(Type type, byte[] data, string encRules)
    {
        MethodInfo methodInfo = typeof(Test).GetMethod("GenericDecodeData").MakeGenericMethod(
            new Type[] { type });
        return methodInfo.Invoke(null, new object[] { data, encRules });
    }
}

string.Format("{0:0000-0000-0000}", 123456789012);