in C++ there is a function for strings find which has the syntax Str.find(substr) which returns the start index of the substring if it exists. I was wondering if anyone knows of a function that provides the same functionality in VB.Net. I have not been able to find one in my searches thus far.
Dim x as String ="ijoneodfpmwfg"
Dim i as Integer = x.IndexOf("d")
'i will be 6 after execution
You shoul really look at this page for that answer. It will tell you all the things you can do with a string and you may find other answers to questions, before you have to ask them here:
String Class
Related
Im using the FolderBrowserDialog to pick a path.
It will return for ex. this= C:\Mypath1\Mypath2\DOCS
I would like to remove everything but DOCS.
If i use VBA i would use a InStrRev combined with a left. But now in in VB.net and im not sure how to achieve this, im pretty sure there is something better than my old VBA way?
Anyone there that could help, google failed me.
Try this:
IO.Path.GetFileName("C:\Mypath1\Mypath2\DOCS")
Which returns DOCS.
I am not sure what you want to do. But maybe this can help you get the last part of a string
Dim fullPath As String = " C:\Mypath1\Mypath2\DOCS"
Dim Parts As String() = fullPath.Split("\")
Dim lastPart As String = Parts(Parts.Length - 1)
I am writing a program in Visual Basic that writes and reads to and from a Microsoft Access Database. When reading from the database, one of the functions that I am trying to perform is to determine the number of lines in a multi-line string that was written to the database and then subsequently read from the database. Here's what I have tried so far with no luck.
Dim stringLines() As String = databaseReader("multilineString").ToString.Split(CChar("Environment.NewLine"))
Dim stringLinesCount As Integer = stringLines.Length
For some reason, this always results in stringLinesCount being equal to one, regardless of how many lines the string has. In this example, I am using Environment.NewLine, but I have tried \n, \r, vbCr, vbLf, and vbCrLf as well, and they all result in a value of one. Since none of these seem to be working, what can I use instead to determine the number of lines?
Edit:
Dim splitCharacters() As Char = {CChar(vbCrLf), CChar(vbCr), CChar(vbLf), CChar(Environment.NewLine), CChar("\n"), CChar("\r")}
Dim stringLines() As String = databaseReader("multilineString").ToString.Split(splitCharacters)
Dim stringLinesCount As Integer = stringLines.Length
Since Chris Dunaway provided the answer that I view as helpful but posted it as a comment, here's what he said:
VB cannot use C# style escape sequences, so CChar("\n") and CChar("\r") is meaningless in VB. Also, calling CChar("Environment.NewLine") is wrong because you are trying to convert the actual string "Environment.NewLine" to a single character, which obviously won't work. You can just use Environment.Newline directly in the call to String.Split.
If Chris decides to post his comment as an answer, please let me know so that I may remove this.
I'm just looking for some ideas with a little problem. I've a string that's a template for a message, for example:
Dear [[Guest.FirstName]],
We hope your are looking forward to your holiday in [[Booking.ResortName]]
My current system for replacing the spaceholder tokens (e.g. [[Guest.FirstName]]) is very inefficient, there's loops inside loops and it takes for too long.
What I'm looking for is a way that would go through the string until it finds [[something]], then replace that [[something]] with it's real value, then continue on through the string.
Please note to replace [[something]] then I need to have access to the space holder (i.e. i need to know if it's [[Guest.FirstName]] or [[Booking.ResortName]]).
Any suggestions for an efficient way to achieve this would be very much appreciated, I feel it should be fairly straightforward but everything I can think of ends up with loops inside loops again.
Thanks!
Phil.
There are many factors which will affect performance, so it's hard to say, without knowing all the specifics, what method will be most efficient. However, when it comes to coding simplicity, using a RegEx MatchEvaluator would be an excellent option. I'm sure you'll agree that it's much cleaner than whatever you are currently using:
Public Function ReplacePlaceholders(data As String) As String
Dim r As New Regex("\[\[(?<placeholder>.*?)\]\]")
data = r.Replace(data, New MatchEvaluator(AddressOf PlaceHolderReplacementEvaluator))
End Function
Private Function PlaceHolderReplacementEvaluator(match As Match) As String
Dim name As String = match.Groups("placeholder").Value
Return LookUpValueByPlaceholderName(name) ' Replace with value lookup logic here
End Function
If the total number of placeholders in the data is going to be rather small, and the list of possible placeholders is small, it's probably best to just have a list of them with their values and replace them like this:
Public Function ReplacePlaceholders(data As String) As String
Dim placeHolders As Dictionary(Of String, String) = LoadPlaceHolders()
For Each i As KeyValuePair(Of String, String) In placeHolders
data = data.Replace(i.Key, i.Value)
Next
Return data
End Function
Private Function LoadPlaceHolders() As Dictionary(Of String, String)
Dim placeholders As New Dictionary(Of String, String)
' Load data here
Return placeholders
End Function
If you really want the most efficient solution, though, going character by character and appending, as you go, to a StringBuilder or an output Stream, is going to be your best option. It's not going to be pretty, but if you post what you have to CodeReview, there may be some people who could find ways of making it slightly less ugly :)
Using VBA, I am trying to convert a string such as "/10" into an arithmetic operation, so that if I somehow connect it (depending on how it gets converted) after the number 200, the number 20 would be returned.
Thanks for any help.
What you're looking for is called a Math Parser. Look around for a library that you can use in VBA. If you're working in excel specific stuff - I'm sure excel already has a math parser built in - though I have no idea how you can gain access to it as the programmer. Maybe stick the expression in a cell as a string and call Eval().
EDIT
Microsoft intentionally removed this feature from function calls in excel, however it can be reinstated by creating the following function:
Function Eval(Ref As String)
Application.Volatile
Eval = Evaluate(Ref)
End Function
Then just call Eval("200" & "/10")
EDIT2
As noted in the comments below, modern versions of VBA support
Application.Evaluate("200" & "/10")
the below example provides a way of accomplishing what you are looking for.
Dim s As String
s = "/10"
Dim i As Integer
i = 200
Dim v
v = Evaluate(CStr(i) & s)
MsgBox v
So I've been going around the internet looking for a way to convert regular text(string) into base64 string and found many solutions. I'm trying to use:
Dim byt As Byte() = System.Text.Encoding.UTF8.GetBytes(TextBox1.Text)
TextBox2.Text = convert.ToBase64String(byt)
but it end up with an error saying
'ToBase64String' is not a member of 'System.Windows.Forms.Timer'.
What do I do to fix this? Or if there's a better way to code it please help.
Use System.Convert.ToBase64String(byt). Otherwise the timer is picked up as the innermost matching name.
Not the best name for a timer btw.