Multiple users updating Excel from windows form

I have created a form in Visual Studio 2013 which is used to enter data in Excel by multiple users at same time. It works perfectly fine except if two users open form at the same time or if one has clicked submit and the form is still processing. Then it shows the following error for the other person:

Quote:

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Unhandled exception has occurred in your application. Exception from HRESULT: 0x800A03EC

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How do I disable the command button so that when one user clicks on submit, for other users the form shows the button disabled till the data is being processed?

Code:

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Imports excel = Microsoft.Office.Interop.Excel
Imports System.Runtime.InteropServices

Public Class Form1
    Dim xlapp As New excel.Application
    Dim workbook As excel.Workbook
    Dim worksheet As excel.Worksheet

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
        workbook = xlapp.Workbooks.Open("2.xlsx")
        xlapp.Visible = False
        worksheet = workbook.Sheets("sheet1")
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        If workbook.MultiUserEditing Then
            workbook.AcceptAllChanges()
            workbook.Save()
        End If

        Dim row As Long
        Dim alpha As Long = 0
        row = 5
        With worksheet
            Do While .Cells(row, 4).value IsNot Nothing
                row = row + 1
            Loop

            .Cells(row, 2).value = Me.fname.Text
            .Cells(row, 3).value = Me.lname.Text
            Me.fullname.Text = Me.fname.Text + Me.lname.Text
            .Cells(row, 4).value = Me.fullname.Text
        End With
        xlapp.DisplayAlerts = False
        workbook.SaveAs("2.xlsx", AccessMode:=excel.XlSaveAsAccessMode.xlShared)
    End Sub
End Class

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Doing what you are describing is difficult, because you would need a "server" type program to "tell" all your users using your program when the form is being worked on, and when it's clear.

What would be much easier to do is to identify and handle the error you're getting on the small chance a user DOES click the "Go" button while the file is open in someone else's program.
As a side note, this is EXACTLY the reason databases were invented.

If you use a Try...Catch...End Try block to handle the error, when a user clicks the button and the program hits that error, instead of crash, you can instead "handle" it by making a popup with something like "The file is currently being updated by another user, please wait a little while and try again"

Quote:

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Originally Posted by Jenner

Doing what you are describing is difficult, because you would need a "server" type program to "tell" all your users using your program when the form is being worked on, and when it's clear.

What would be much easier to do is to identify and handle the error you're getting on the small chance a user DOES click the "Go" button while the file is open in someone else's program.
As a side note, this is EXACTLY the reason databases were invented.

If you use a Try...Catch...End Try block to handle the error, when a user clicks the button and the program hits that error, instead of crash, you can instead "handle" it by making a popup with something like "The file is currently being updated by another user, please wait a little while and try again"

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I can't use any database as my users only want excel and this visual studio form. Can you pleas help me with the code of try catch? I am unable to understand.

Here: https://lmgtfy.com/?q=try+catch+vb.net

After you've taken twelve seconds to try to understand it yourself (because you didn't even try apparently), come back if you have any problems with your modified code.