1.函数名是forceNetwork()，而不是forceDirect()。
1.参数名称是NodeID，而不是NodeId。
1.如果将opacity参数设置为0，则不会看到任何内容。

1. Links Dataframe 的Source和Target列中的值必须是数字，并标识它们所引用的Nodes Dataframe 的零索引行。

# your data
Links <- 
  read.table(header = TRUE, stringsAsFactors = FALSE, text = "
    Source  Target  Value
    A       B       1
    B       A       1
    AB      BA      1 
    A       C       1 
    C       A       1 
    AC      C       1
  ")

Nodes <- 
  read.table(header = TRUE, stringsAsFactors = FALSE, text = "
    Id  Name  Group
    0   A     1
    1   B     1
    2   C     1
    3   AB    1
    4   AC    1
    5   BA    1
  ")

# convert Source and Target to zero-indexed row of Nodes
Links$Source <- match(Links$Source, Nodes$Name) - 1
Links$Target <- match(Links$Target, Nodes$Name) - 1

# plot
library(networkD3)
forceNetwork(
  Links = Links, 
  Nodes = Nodes,
  Source = "Source", 
  Target = "Target",
  Value = "Value", 
  NodeID = "Name", 
  Group = "Group",
  opacity = 1
)