New Post: Creating DataFrame In Memory

If you are using R.NET 1.5.5 I think you can do the following (caveat: I did not run a test)

REngine e;
int[] yourIntegers;
double[] yourDoubles;
// etc.
e.SetSymbol("a", e.CreateIntegerVector(yourIntegers))
e.SetSymbol("b", e.CreateNumericVector(yourDoubles))

var df = e.Evaluate("data.frame(nameForA=a, nameForB=b)").AsDataFrame();

I am currently looking at adding a extension function to facilitate creating data frames, which will make it to what may be called version 1.6 in a few weeks.