Using the "Enter" Event

Gary108 · #1 (**permalink**) March 9th, 2012, 10:48 AM

Hi Rod,

I have another question. In my application, I have a button, a text box and TreeView Control where I will create a tree view list. With the button control I can successfully add a node to the Tree View Control. The contents of that node is what is entered in TextBox1. In addition to being able to using a button to add the node to the Tree View Control, I want to be able to just hit the "Enter" button and have it activate btnLevelOne. I am trying to do this using the Enter Event but it seems to have no affect. My code is below. Can you tell me where I am going wrong?

Thanks,

Gary

Code:

Public Class CreateIndex
        'Create a Root Level Node
        Private Sub btnLevelOne_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLevelOne.Click

            Dim NewNodes As String
            NewNodes = TextBox1.Text
            TreeView1.Nodes.Add(NewNodes)

            TextBox1.Clear()

        End Sub
        Private Sub TextBox1_Enter(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.Enter

            btnLevelOne.Focus()
            SendKeys.Send("{Enter}")

        End Sub
    End Class

Rod Stephens · #2 (**permalink**) March 9th, 2012, 11:40 AM

Hi Gary,

I'm not sure why this isn't working. Possibly focus has not finished moving to the button before you send {Enter}. You could try to use Application.DoEvents to slow the program down enough so focus moves.

SendKeys seems to get harder to use with each new release. I suspect Microsoft isn't really trying to maintain it.

What I would do is making the button be the form's AcceptButton so the form fires it if you press Enter. Then you don't need the Enter event handler.

If that doesn't work, I would move the body of the button's event handler into a new subroutine. Then you can have the button and the TextBox's Enter command both call the new subroutine. That way they both call the code directly and you don't need to duplicate the code.

Gary108 · #3 (**permalink**) March 9th, 2012, 10:45 PM

Hi Rod,

Yes, Thank you. Changing the button to an Accept button solved the problem.

I have another question though. I need to write certain words to a text file so that they are inserted in place within the textfile. The text file would not have any duplicate words. For example, if the list was:

car
truck
bicycle
boat

and I wanted to automatically insert the word "SUV" after "truck", how could I do it? I know I can loop down the list and find a particular word, but I am uncertain how to insert "SUV" directly after "truck".

Thank you for your ongoing help.

Gary

Rod Stephens · #4 (**permalink**) March 12th, 2012, 11:12 AM

(Please start a new thread for new topics so they're easier for others to find in the discussion.)

Sorry but you can't do that.

A text file is just a stream of bytes all adjacent on the disk so you can't insert or remove bytes in the middle.

That doesn't really hurt you here, though. Just read the file into an array (use ReadAllLines), add the new items where you want them, and rewrite the file (use WriteAllLines). It may sound inefficient but it should be very fast.

In this case, adding the SUV in the middle of the list is probably going to be the trickiest part. You may want to convert the array into a list, insert the new entry, and then use WriteAllLines to rewrite the file. WriteAllLines can take a list as a parameter instead of an array so you don't need to convert back.

If you want to ensure there are no duplicates, then you may want to look at LINQ.

I hope that helps.

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