String Builder Appending value in middle of existing appendage

Question

I have Dims I am referencing to Append a String, however my requirement requests that I split up one of my previous Dims I am appending. Please see the example below to show you what i am trying to get at. Basically i need a way for my newest Dim added to go smack dab in the middle of an existing Dim that's already been appended. **Note: Dim a can be dynamic so I don't know the number of characters it will return.

I am using the StringBuilder functionality in VB.

Dim sb = New StringBuilder()

Dim a = someValueForA

Dim b = someValueForB

Dim c = someValueForC

Dim d = someValueForD

sb.AppendFormat("-{0}",a)
sb.AppendFormat("-{0}",b)
sb.AppendFormat("-{0}",c)

result = "someValueAsomeValueBsomeValueC"

now i need to insert d right in the middle of "C" so as to look something like this:

result = "someValueAsomeValueBsomesomeValueDValueC"

Answer 1

You need to calculate the position and then use sb.Insert:

Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
   Dim sb = New StringBuilder()
   Dim a = "someValueA"
   Dim b = "someValueB"
   Dim c = "someValueC"
   Dim d = "someValueD"

   sb.AppendFormat("-{0}", a)
   sb.AppendFormat("-{0}", b)
   sb.AppendFormat("-{0}", c)
   sb.Insert(sb.Length - (c.Length \ 2), d)

   MessageBox.Show(sb.ToString())
End Sub