error with RBGL package in R - r

Question

I want to install the RGBL package in bioconductor to perform some graph algorithms.
I updated R to the latest version 3.2.0, and installed the package as instructed on http://www.bioconductor.org/
source("http://bioconductor.org/biocLite.R")
biocLite("RBGL")
It was installed successfully, then I tried to run
library(graph)
library(RBGL)
x<- strongComp(graph)
and returns this error
Error in (function (classes, fdef, mtable) :
unable to find an inherited method for function ‘isDirected’ for signature ‘"igraph"’
Here's the traceback
> traceback()
4: stop(gettextf("unable to find an inherited method for function %s for signature %s",
sQuote(fdef#generic), sQuote(cnames)), domain = NA)
3: (function (classes, fdef, mtable)
{
methods <- .findInheritedMethods(classes, fdef, mtable)
if (length(methods) == 1L)
return(methods[[1L]])
else if (length(methods) == 0L) {
cnames <- paste0("\"", vapply(classes, as.character,
""), "\"", collapse = ", ")
stop(gettextf("unable to find an inherited method for function %s for signature %s",
sQuote(fdef#generic), sQuote(cnames)), domain = NA)
}
else stop("Internal error in finding inherited methods; didn't return a unique method",
domain = NA)
})(list("igraph"), function (object)
standardGeneric("isDirected"), <environment>)
2: isDirected(g)
1: strongComp(graph)
My system is Windows 32-bit.
I'm not sure if this is enough information. Please let me know if any other information needed.
Any ideas are appreciated, thanks!
EDIT:
I used the igraph packaged to create the graph object from an edge list with weight
library(igraph)
graph<- graph.data.frame(edge.list[,c(2:4)],directed=TRUE)
I'm not very good with generating random number, here's a reproducible example for my graph
set.seed(123)
edge.list<-cbind(seq(10),c(1,1,2,3,3,4,5,5,5,5),c(2,2,3,5,4,3,4,4,4,2),
runif(10, 1, 30))
colnames(edge.list) <-c("ID","V1","V2","weight")

Answer 1

As pointed out in the comments, you need to make a graph object, not an igraph object.
Here's how I might transform your edge.list into the form that graph expects.
rawEL <- data.frame(source = as.character(edge.list[,1]),
edges = as.character(edge.list[,2]),
weights = edge.list[,3], stringsAsFactors=F
)
V <- unique(c(rawEL$source, rawEL$edges))
edL <- lapply(
split(
rawEL[,-1],
factor(edge.list[,1], levels=V)
), as.list
)
gr <- graphNEL(V, edL, "directed")
plot(gr)