how format twine write array c#

i have twine "1112224444' write number. i wish format 111-222-4444 before i store file. datarecord i move means but assigning new variable.

i thinking:

string.format("{0:###-###-####}", i["myphone"].tostring() );

but does seem trick.

** transform **

ok. i went solution

convert.toint64(i["customer phone"]).tostring("###-###-#### ####")

now the gets messed adult progression reduction 4 digits. fill numbers right. so

1112224444 333  becomes

11-221-244 3334

any ideas?