File Exists

[MacShand]

Hello

I have the following code:

   If Dir("C:\Test.txt") <> "" Then
            TextBox1.Text = "File exists"
        Else
            TextBox1.Text = "File does not exist"
        End If

However, I'd like to use this alongside a DataGridView.

Basically, when the application runs, the user selects a folder for file storage. Then, in the DataGridView, the contents in each cell of Column 1 become the file name. In short, the contents of a cell, plus the selected folder for file storage, becomes a whole file path.

I need to use the above code to get my application to check if the file exists, and if it does, it should place the text "File Exists" in column 2 of the DGV.

I can't work out a way for the DGV to be "continually aware" if files have been created and so to update automatically without the user having to press buttons etc. As soon as the file exists, the correct text should be placed in Column2.

Thanks for the help!

M

[John_SC]

For it to be aware of changes to your file system, the operating system would have to issue some sort of an alert which you are monitoring, or you would have to monitor it yourself. I am not aware of any standard trigger inside the operating system, so the easiest way would for you to regularly poll your file system.

Pick a time period for your poll. Too fast will add a lot of overhead to your system and slow things down. Say 1 minute (or whatever time frame you pick). You would use a timer, and when it triggers, check your file system. This would need to continually run in the background to work.

[proneal]

Check out the BackgroundWorker Class

[Chris001]

Do not use Dir, that's VB6 code.

Use File.Exists instead. Add "Imports System.IO".

[proneal]

Do not use Dir, that's VB6 code.

Use File.Exists instead. Add "Imports System.IO".

Yes OP, Get with the Program

[Niya]

Do not use Dir, that's VB6 code.

I don't know why MS didnt remove that. It is such utter trash even in VB6. The FindFirstFile API and its family are vastly superior. I stopped using Dir in VB6 in favour of those APIs.

[ident]

May above reason not to use dir

Dim f As String = "C:\file.txt"
Dim flags As FileAttributes = File.GetAttributes(f)
File.SetAttributes(f, FileAttributes.Normal)
MsgBox(String.Format("File exist {0} {1}", Dir(f) <> Nothing, IO.File.Exists(f) <> Nothing))
File.SetAttributes(f, FileAttributes.Hidden)
MsgBox(String.Format("File exist {0} {1}", Dir(f) <> Nothing, IO.File.Exists(f) <> Nothing))