Concatenate strings with vb6

I am trying to concatenate in vb6. The operator += is not supported, and I want to do something like the code below. I want to add more strings to a textbox as the program works down this code. Can anyone advise what to change += to? I know & can be used when adding one string to another, but it the example I am working on here, that doesn't seem suitable. Thanks. ``` If (strHomeNo <> "") Then txtPhoneNums = "Home: " + strHomeNo End If If (strMobileNo <> "") Then txtPhoneNums += "Mobile: " + strMobileNo End If If (strWorkNo <> "") Then txtPhoneNums += "Work: " + strWorkNo End If If (txtPhoneNums <> "") Then txtPhoneNums.ForeColor = vbBlack txtPhoneNums.FontBold = False End If Else txtPhoneNums.Text = "NO CONTACT DETAILS" txtPhoneNums.ForeColor = vbRed txtPhoneNums.FontBold = True ```