[vb.net] Find the index of a char in string?

I have a string that goes like "abcdefg..."

I would like to find the index where the letter d is at, so I can get the number 3.

I managed to do it by looping through each letter in the string, but that doesn't sound very convenient. Is there another way?

"abcdefgh..".IndexOf("d")

returns 3

In general returns first occurrence index, if not present returns -1

Contanis occur if using the method of the present letter, and store the corresponding number using the IndexOf method, see example below.

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Dim myString As String = "abcdef"
    Dim numberString As String = String.Empty

    If myString.Contains("d") Then
        numberString = myString.IndexOf("d")
    End If
End Sub

Another sample with TextBox

  Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Dim myString As String = "abcdef"
    Dim numberString As String = String.Empty

    If myString.Contains(me.TextBox1.Text) Then
        numberString = myString.IndexOf(Me.TextBox1.Text)
    End If
End Sub

Regards