FileNotFoundException was unhandled

Question

 I have a program that can save user's input into a text file and load it back, but whenever I try to open a text file and exit without selecting the file I get an error.(if i select the file and open it i don't get any errors).

this is the code that handles text file loading

Private Sub Button4_Click(sender As System.Object, e As System.EventArgs) Handles Button4.Click
        OpenFileDialog1.InitialDirectory = "C:\"
        OpenFileDialog1.Filter = "Text Files ONLY (*.txt) | *.txt"
        OpenFileDialog1.ShowDialog()
        Dim loader As New IO.StreamReader(OpenFileDialog1.FileName)
        TextBox1.Text = loader.ReadLine
        TextBox2.Text = loader.ReadLine
        TextBox3.Text = loader.ReadLine
        TextBox4.Text = loader.ReadLine
        TextBox5.Text = loader.ReadLine
        TextBox6.Text = loader.ReadLine
        TextBox7.Text = loader.ReadLine
        TextBox8.Text = loader.ReadLine
        TextBox9.Text = loader.ReadLine
        TextBox10.Text = loader.ReadLine
        TextBox11.Text = loader.ReadLine
        TextBox12.Text = loader.ReadLine
        TextBox13.Text = loader.ReadLine
        TextBox14.Text = loader.ReadLine
        TextBox16.Text = loader.ReadLine
        TextBox57.Text = loader.ReadLine
        loader.Close()
    End Sub

the error is :"FileNotFoundException was unhandled. Could not find file at xxx"
also I would like to know how to make it so that the initial file name for file saving is today's date. Thanks.

Answer 1

First thing: you can erase all the ReadLine and use ReadtoEnd (this will not solve the error, but if the textboxes are multiline so you need to read all the lines);

Second Thing: you can use a Try...Catch...End Try, this will prevent your app to close or raise an event. Under Catch you'll write what the program should do in case of an error.

Third Thing: verify that FileName... is a filename :D I mean that if you write an invalid name such as an empty name, a name with strange characters or something else it will crush... The error you posted show this problem: the file name you specified is not valid.

Answer 2

Hi Hearsemobile,

Welcome to the MSDN forum.

You get the error because whether you choose the file to open or not, the following code will be run:

  Dim loader As New IO.StreamReader(OpenFileDialog1.FileName)
        TextBox1.Text = loader.ReadLine
        ……

When you not give the filename, the loader can’t open the file, and will give you an error. So I suggest you to put all the code in a “if … end if” block, here is a sample:

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        Dim openFileDialog1 As New OpenFileDialog()
        openFileDialog1.InitialDirectory = "C:\"
        openFileDialog1.Filter = "Text Files ONLY (*.txt) | *.txt"
        openFileDialog1.ShowDialog()
  
        If openFileDialog1.ShowDialog() = System.Windows.Forms.DialogResult.OK Then
            Try
                Dim loader As New IO.StreamReader(openFileDialog1.FileName)
                TextBox1.Text = loader.ReadLine
                '......
                loader.Close()
            Catch Ex As Exception
                MessageBox.Show("Cannot read file from disk. Original error: " & Ex.Message)
            End Try
        End If
    End Sub

The below sample show to your another issue: the initial file name for file saving is today's date. It is showed in the SaveFileDialog:
 

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        Dim saveFileDialog1 = New SaveFileDialog()
        saveFileDialog1.CreatePrompt = True
        'saveFileDialog1.FileName = Date.Now 
        saveFileDialog1.FileName = Date.Now.Date
        saveFileDialog1.Filter = "Text Files ONLY (*.txt) | *.txt"
        If saveFileDialog1.ShowDialog() = DialogResult.OK Then
            'add your code
        End If
    End Sub

If you have any additional questions, please feel free to let me know.

---

Mark Liu-lxf [MSFT]
MSDN Community Support | Feedback to us

Answer 3

Hi Hearsemobile,

We haven’t heard from you for a while. I’d like to mark my reply as answer firstly. If you have any additional questions, you also can unmark the replay and post your question here. 

Sorry for any inconvenience and have a nice day.

---

Mark Liu-lxf [MSFT]
MSDN Community Support | Feedback to us