CODEWITHSUNDEEP
.netvb.netstringsubstring
Catalin Cernat
Catalin Cernat

Reputation: 137

Substring - argument out of range exception - startIndex parameter

Assume that I have the following string in TextBox1: FPO100200%10&FORD*

Now, i have 2 more textboxes that gets data from substrings of textbox1. I have the following code:

Public Class Form1
Private Function textmoves(mytext As String, indexchar As String)
    Dim Index As Integer = mytext.IndexOf(indexchar)
    Return Index
End Function
Private Sub Splittext()
    Dim text As String = TextBox1.Text
    TextBox2.Text = text.Substring(0, textmoves(text, "%"))
    TextBox3.Text = text.Substring(textmoves(text, "%"), textmoves(text, "&"))
End Sub

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Splittext()
End Sub

End Class

Im trying to get in texbox2 the substring FPO100200, then in texbox3 the substring 10.

As soon as I added the line with textbox3, it threw me an argument out of range error. Can you tell me what im doing wrong? Thanks alot!

LE: Also, how can I make that textboxes to populate with data when text changed in textbox1, automatically, without pressing the button?

Upvotes: 1

Views: 691

Answers (2)

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726569

Second parameter is length, not end position. The reason the first expression worked with position is that the initial index is zero.

To get "10" use

TextBox3.Text = text.Substring(textmoves(text, "%")+1, textmoves(text, "&")-textmoves(text, "%")-1)

or better

Dim pos As Integer = textmoves(text, "%")
TextBox2.Text = text.Substring(0, pos)
TextBox3.Text = text.Substring(pos+1, textmoves(text, "&")-pos-1)

Demo.

Upvotes: 1

David Sdot
David Sdot

Reputation: 2333

Your second parameter is the Index of the & when you start at index 0 but you're begining at the index of %. So you need to substract %Index from &Index.

TextBox3.Text = text.Substring(textmoves(text, "%"), textmoves(text, "&") - textmoves(text, "%"))

Upvotes: 1

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