Process question

Is there a way to trap an event relating to trying to start a process when the computer lacks the application. For instance doing a process.start on a MS Project file when the computer lacks the application. Now my application just hangs when that occurs.

Thanks,
Fred

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Process question

d.v.d

I'm assuming you are not using "ProcessStartInfo" take alook there are several methods and properties to handle non-start errors such as:

Public Property ErrorDialogParentHandle() As System.IntPtr

Member of: System.Diagnostics.ProcessStartInfo

Summary:

Gets or sets the window handle to use when an error dialog is shown for a process that cannot be started.

and

Public Property ErrorDialog() As Boolean

Member of: System.Diagnostics.ProcessStartInfo

Summary:

Gets or sets a value indicating whether an error dialog is displayed to the user if the process cannot be started.
Hitesh Shah

I thought I might be easier to repose my question about process.start with my code. I have embedded my start event in a try/catch. In this example I am trying to launch MS Project and open a .mpp file. Unformtunately the computer does not have the application installled. Instead of raising an exception, the application hangs. I would like to know either how to trap the error or determine via software if the client computer has the target application installed.

Thanks,
Fred

Private Sub LoadProject(ByVal selectedRow As DataRow)
        Dim DataType As String = "Project"
        Dim BLOB() As Byte

        'Load the encrypted encryped file from the server
        Try
            If CInt(selectedRow("Project")) = 1 Then
                BLOB = LoadBLOBData(DataType, CStr(selectedRow("ID")))
            Else
                Exit Sub
            End If
        Catch MyException As Exception
            StatusMessage.Clear()
            StatusMessage.Text = "Error on documnet load due to: " & MyException.message
            Exit Sub
        End Try

        'Create a process and display the document
        Try
            Dim filepath As String = "c:\program files\ApplicationData.mpp"
            Dim fs As New FileStream(filepath, FileMode.OpenOrCreate, FileAccess.Write)
            fs.Write(BLOB, 0, CInt(BLOB.Length))
            fs.Close()
            XMainForm.Visible = False
            Dim proc As New System.Diagnostics.Process
            proc.StartInfo.UseShellExecute = True
            proc.StartInfo.FileName = filepath
            proc.Start()
            While Not proc.HasExited
            End While
            StatusMessage.Clear()
            StatusMessage.Text = "Application exited with exitcode: " + proc.ExitCode.ToString()
            proc.Dispose()
            XMainForm.Visible = True
        Catch MyException As Exception
            StatusMessage.Clear()
            StatusMessage.Text = "Unable display requested file due to: " & MyException.message
        End Try
    End Sub
Karv
You could use com-interop to check if the application can be instantiated, rather than trying to start it as a seperate process. You can trap any errors in that code easily. Theres an example of using project com-interop and the Project Objectmodel here

Cathal

Pacific Ocean Blue

your app is hanging because of the never ending loop:

While Not proc.HasExited
End While

Get rid of the loop and add

proc.StartInfo.ErrorDialog = True

so your code will look like this:

Dim proc As New System.Diagnostics.Process
           proc.StartInfo.UseShellExecute = True
           proc.StartInfo.ErrorDialog = True
           proc.StartInfo.FileName = filepath
           if Not proc.Start() then
            ...
           end if

Public Function Start() As Boolean

Member of: System.Diagnostics.Process

Summary:

Starts (or reuses) the process resource that is specified by the System.Diagnostics.Process.StartInfo property of this System.Diagnostics.Process component and associates it with the component.

Return Values:

true if a process resource is started; false if no new process resource is started (for example, if an existing process is reused).

Exceptions:

System.ObjectDisposedException: The process object has already been disposed.

System.ComponentModel.Win32Exception: There was an error in opening the associated file.

System.InvalidOperationException: No file name was specified in the System.Diagnostics.Process component's System.Diagnostics.Process.StartInfo.-or- The System.Diagnostics.ProcessStartInfo.UseShellExecute member of the System.Diagnostics.Process.StartInfo property is true while System.Diagnostics.ProcessStartInfo.RedirectStandardInput, System.Diagnostics.ProcessStartInfo.RedirectStandardOutput, or System.Diagnostics.ProcessStartInfo.RedirectStandardError is true.

Process question

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