var myMethod = myInstance.GetType()
.GetMethods()
.Where(m => m.Name == "MyMethod")
.Select(m => new {
Method = m,
Params = m.GetParameters(),
Args = m.GetGenericArguments()
})
.Where(x => x.Params.Length == 1
&& x.Args.Length == 1
&& x.Params[0].ParameterType == x.Args[0])
.Select(x => x.Method)
.First();