Arrow keys don't seem to work? - vb.net

I am trying to make a maze game however this is the only code I can't seem to get to work. I want the picture box (the player) to move in the direction of the arrow keys.
I have tried this code:
Private Sub BLevel1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
If e.KeyCode = 37 Then
PictureBoxPlayer.Left = PictureBoxPlayer.Left - 10
ElseIf e.KeyCode = 38 Then
PictureBoxPlayer.Top = PictureBoxPlayer.Top - 10
ElseIf e.KeyCode = 39 Then
PictureBoxPlayer.Left = PictureBoxPlayer.Left + 10
ElseIf e.KeyCode = 40 Then
PictureBoxPlayer.Top = PictureBoxPlayer.Top + 10
End If
End Sub
I have also tried location codes but the arrow keys don't seem to move the picture box. This is the only issue I am running into.
Any ideas on how I can resolve this?

The cursor keys are special, they are used to navigate the focus from one control to another. So they are normally intercepted before they get to the control that currently has the focus. Furthermore, you wrote a KeyDown event for the form, it won't have the focus when the form has other controls so won't get the KeyDown event. It is unclear whether that applies here.
The best way to go about it is to intercept the cursor keys yourself, before they can be used elsewhere. You do so by writing an override for the form's ProcessCmdKey() method, like this:
Protected Overrides Function ProcessCmdKey(ByRef msg As Message, keyData As Keys) As Boolean
If keyData = Keys.Left Then
PictureBoxPlayer.Left = Math.Max(0, PictureBoxPlayer.Left - 10)
Return True
ElseIf keyData = Keys.Right Then
PictureBoxPlayer.Left = Math.Min(Me.ClientSize.Width - PictureBoxPlayer.Width, PictureBoxPlayer.Left + 10)
Return True
ElseIf keyData = Keys.Up Then
'' etc..
End If
Return MyBase.ProcessCmdKey(msg, keyData)
End Function
I threw in the code to prevent the user from moving the player outside of the form. Finish the code by writing the Keys.Up and Keys.Down code.

Why don't you try to use Listbox1, make an image array and bring the listbox1 to back so it cant be seen, then addrange the listbox1 from the Folder Path of the image folder, It seems like simple image viewer.
You can try this
use the button or anything with click method
Dim myimg As Array
Private Sub img_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles img.Click
If FolderBrowserDialog1.ShowDialog = DialogResult.OK Then
myimg = IO.Directory.GetFiles(FolderBrowserDialog1.SelectedPath)
ListBox1.Items.AddRange(myimg)
ListBox1.SelectedIndex = 0
End If
End Sub
Then set the tab index to 1 on the listbox
then click twice the listbox1 and insert this
Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
Me.Refresh()
Me.BackgroundImage = Nothing
Me.BackgroundImage = Image.FromFile(ListBox1.SelectedItem.ToString)
End Sub
Use your arrow key, image will automatically change.
You can change Me to Picturebox.
Hope it helps

Related

Detect when a user stops editing a DataGridViewCell

I am working on a VB.Net project and am trying to set up a DataGridView so that users can edit data. I'd like to set it up so that when a user finishes editing a cell, either through navigating to a new cell, or by pressing the Enter key, something happens.
I started by creating a method to store the old data that was in the cell:
Private oldCellVal As String = ""
Private oldCellRow As Integer
Private oldCellCol As Integer
Private Sub dg_CellBeginEdit(ByVal sender As Object, ByVal e As DataGridViewCellCancelEventArgs) Handles dg.CellEndEdit
oldCellVal = dg.Rows(e.RowIndex).Cells(e.ColumnIndex).Value
oldCellRow = e.RowIndex
oldCellCol = e.ColumnIndex
End Sub
Now my next logical step was to create a KeyDown event for the DataGridView
Private Sub dg_KeyDown(ByVal sender As Object, ByVal e As KeyEventArgs) Handles dg.KeyDown
If e.KeyCode <> Keys.Enter Then
If dg.IsCurrentCellInEditMode() Then
If MessageBox.Show("Would you like to cancel editing?", "Confirmation", MessageBoxButtons.YesNoCancel) = DialogResult.Yes Then dg.CurrentCell.Value = oldCellVal
End If
ElseIf e.KeyCode = Keys.Enter Then
If MessageBox.Show("Would you like to save these changes?", "Confirmation", MessageBoxButtons.YesNoCancel) = DialogResult.Yes Then MessageBox.Show("Saved")
End If
End Sub
Well here we have our first problem. While the DataGridView is in edit mode for a cell, it does not register KeyDown events. No matter what I did, I could not trigger the KeyDown event handler until after moving to another cell. Essentially I need to hit Enter twice in order for the MessageBox to appear.
So from here I figured, okay, lets put together an event handler for EditingControlsShowing that should work!
Private Sub dg_EditingControlsSHow(ByVal sender As Object, ByVal e As DataGridViewEditingControlShowingEventArgs) Handles dg.EditingControlShowing
MessageBox.Show("Please work")
End Sub
And here the MessageBox only appears once the editting has begun, and I can do nothing once I am finished.
So I am utterly confused as to what to do here. To restate what I want to do I am trying to set up a DataGridView that has the following functionality for the Cells:
While editing the value within a Cell, if you press the Enter key, you get a prompt asking if you want to save your changes.
If instead of Enter, you press any other key that would turn off Cell editing (like Tab or the Arrow Keys) you get a prompt asking if you are sure you wish to cancel editing.
I really don't know what to do here, so any and all help is greatly appreciated.
First you need to check if you are in edit mode:
Private isEditing As Boolean = False
Private Sub DataGridView1_CellBeginEdit(sender As Object, e As DataGridViewCellCancelEventArgs) Handles DataGridView1.CellBeginEdit
isEditing = True
End Sub
Private Sub DataGridView1_CellEndEdit(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellEndEdit
isEditing = False
End Sub
Then you can override the ProcessCmdKey function:
Protected Overrides Function ProcessCmdKey(ByRef msg As Message, keyData As Keys) As Boolean
If isEditing = True Then
Select Case keyData
Case Keys.Left
Case Keys.Right
Case Keys.Enter
Case Else
End Select
End If
Return MyBase.ProcessCmdKey(msg, keyData)
End Function
Return True from the function if you want to suppress the key.

Can't get KeyDown event on Tabpage

I have a TabControl with several TabPages, each containing a series of PictureBox. I want to be able to navigate with the arrow keys inside those TabPages. I tried to give .Focus() to the TabPage when the user selects it, and then trap the PreviewKeyDown and KeyDown events, but it does not work. I've put a breakpoint at the PreviewKeyDown event handler, and it is not event reached.
Here is the activation of the TabPage :
Sub TilesetsTab_Selected(ByVal sender As Object, ByVal e As TabControlEventArgs) Handles TilesetsTab.Selected
Dim myTab As TabControl = CType(sender, TabControl)
If myTab.TabCount = 0 Then Exit Sub
Active.Tileset = Project.Tileset(CInt(myTab.SelectedTab.Tag))
Active.Tileset.Tab.Focus()
End Sub
And here is the Key event handlers
Sub Tab_KeyPreviewDown(ByVal sender As Object, ByVal e As PreviewKeyDownEventArgs) Handles Tab.PreviewKeyDown
If e.KeyCode = Keys.Left Or e.KeyCode = Keys.Right Or e.KeyCode = Keys.Up Or e.KeyCode = Keys.Down Then e.IsInputKey = True
End Sub
Sub Tab_KeyDown(ByVal sender As Object, ByVal e As KeyEventArgs) Handles Tab.KeyDown 'BUG
Dim TilesWidth As Integer = Me.Tab.Width \ Me.ScreenSize
Select Case e.KeyCode
Case Keys.Left
If Active.Tile.Index = 0 Then Exit Sub
Me.Tile(Active.Tile.Index - 1).Selected()
Case Keys.Right
If Active.Tile.Index = Project.Tileset.Count - 1 Then Exit Sub
Me.Tile(Active.Tile.Index + 1).Selected()
Case Keys.Up
If Active.Tile.Index < TilesWidth Then Exit Sub
Me.Tile(Active.Tile.Index - TilesWidth).Selected()
Case Keys.Down
If Active.Tile.Index + TilesWidth > Active.Tileset.Count - 1 Then Exit Sub
Me.Tile(Active.Tile.Index + TilesWidth).Selected()
End Select
End Sub
Why can't I fire a KeyDown event on the TabPage ?
I don't know why the answer posted yesterday by someone (and the comments I made) were deleted, but it was said that TabPages could not have focus, and that it is restricted to TabControl. Following that advice, I shifted the PreviewKeyDown and KeyDown event handlers to TabControl events and it worked.
I'm losing some of the arrow navigation between TabPages, but it suits me.

How to change the Location (x,y) of the object by using coding in VB.net?

I Want to say sorry if there was a same question like i had. I have tried to Search but i couldn't find it, so.. i hope there is no other question like this..
To the point, i need your help to tell me how to change the Location of an object in a form
What i want to do is making the Button1 move to the left when i press the left key on the keyboard. But i have a problem with how to set the location (x,y) of the object
Private Sub Button1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Button1.KeyPress
If Asc(e.KeyChar) = Keys.Left Then
End If
End Sub
Thanks ...
By default, the arrow keys are not captured by the control's KeyPress, KeyDown or KeyUp events. You can make them be captured by KeyDown and KeyUp by setting e.IsInputKey to True in the PreviewKeyDown event. Then you can move the button sideways by changing its Left property. The following assumes the button has focus.
Private Sub Button1_PreviewKeyDown(sender As Object, e As PreviewKeyDownEventArgs) _
Handles Button1.PreviewKeyDown
If e.KeyCode = Keys.Left Or e.KeyCode = Keys.Right Then e.IsInputKey = True
End Sub
Private Sub Button1_KeyDown(sender As Object, e As KeyEventArgs) _
Handles Button1.KeyDown
Dim myButton As Button = CType(sender, Button)
If e.KeyCode = Keys.Left Then myButton.Left -= 1
If e.KeyCode = Keys.Right Then myButton.Left += 1
End Sub
Updated Solution
Here's a way to accomplish it so that it moves while holding down the key. Create a project with a Form and Button.
Right-click on the Project in the Solution Explorer and add two .NET References:
PresentationCore
WindowsBase
Here's the code. A timer will capture key events and move the button:
Imports System.Windows.Input
Public Class Form1
Private timex As New Timer
Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
AddHandler timex.Tick, AddressOf myTickEvent
timex.Enabled = True
timex.Interval = 100
End Sub
Private Sub myTickEvent(sender As Object, e As EventArgs)
If isKeyPressed(Key.Left) Then
Me.Button1.Left -= 10
End If
If isKeyPressed(Key.Right) Then
Me.Button1.Left += 10
End If
If isKeyPressed(Key.Up) Then
Me.Button1.Top -= 10
End If
If isKeyPressed(Key.Down) Then
Me.Button1.Top += 10
End If
End Sub
Private Function isKeyPressed(ByRef keys As System.Windows.Input.Key)
If (Windows.Input.Keyboard.GetKeyStates(keys) And Windows.Input.KeyStates.Down) > 0 Then
Return True
Else
Return False
End If
End Function
End Class

ComboBox's SelectedIndexChanged event not being called on Enter

I'm working on VS 2010 with VB using .NET Framework 4.0
I have a combobox. It has some items in it and displays just fine. Here's where it gets a little weird:
If I click the drop-down arrow on the combobox and CLICK on the item I want, SelectedIndexChanged is called - good.
If I click inside the text area of the combobox and start typing what I want selected and finish it by pressing the up (or down) key, SelectedIndexChanged is called - also good.
If I click the drop-down arrow on the combobox and start typing what I want selected and finish it by pressing ENTER, SelectedIndexChanged is not called - PROBLEM.
Is there a different event that is caused by the ENTER in the last case? I've tried using the TextChanged and TextUpdate events, but those do not seem to be working:
Private Sub cmbStatus_TextChanged(sender As System.Object, e As System.EventArgs) Handles cmbStatus.TextChanged
If e.Equals(Keys.Enter) Then
Call SomeMethod()
End If
Should I use something besides e.Equals(Keys.Enter)?
Is there another event I should be looking for?
EDIT:
An example of the items in the ComboBox are:
10 - NEW ENTRY AND COMPLETENESS CHECK ---> this is the most common type
13 - ASSIGNED TO TRB/HRB ---> there are a few with '/'
60 - EXTERNAL (HOLD UNTIL FURTHER NOTICE) ---> there are a few with '(' and ')'
Basically, the type of each listing is "## - SOME TEXT".
Disclaimer: this is written in C# - let me know if you need it translated to VB.
private void comboBox1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
{
//It's important to also check that the Combo Box is displaying its Drop Down. If
//you want this to execute even when it is not displayed, remove the check for
//comboBox1.DroppedDown.
if (e.KeyCode == Keys.Enter && comboBox1.DroppedDown &&
!string.IsNullOrEmpty(comboBox1.Text))
{
int index;
//Attempt to locate the string typed in by the user. An index of -1
//means it was not found.
if ((index = comboBox1.FindStringExact(comboBox1.Text)) != -1)
{
//Update the SelectedIndex.
comboBox1.SelectedIndex = index;
}
}
}
Interestingly, the docs say that we should be using the SelectionChangeCommitted event instead of the SelectedIndexChanged event when handling selection changes made by the user. It is necessary to do so in this case as the SelectedIndexChanged event fires twice using my approach.
Edit:
To prevent the user from having to type the entire string, use the advice from Adi's answer: go to the properties of the combo box and set set AutoCompleteMode to SuggestAppend and AutoCompleteSource to ListItems - I actully used these settings when creating my answer, so it should work for you.
Option Strict On
Public Class Form1
Friend WithEvents ComboBox1 As New ComboBox With {.Parent = Me}
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
ComboBox1.Items.AddRange({"hello", "tes1ted", "word", "item", "tes2ted"})
ComboBox1.Text = ComboBox1.Items(0).ToString
End Sub
Private Sub ComboBox1_KeyUp(ByVal sender As Object, ByVal e As KeyEventArgs) Handles ComboBox1.KeyUp
'You can put this in the keydown event, or adapt it a small bit and put it in the keypress event
'putting it in the textchanged event is problematic and not recommended.
Dim OriginalText As String = ComboBox1.Text
If e.KeyCode = Keys.Enter Then
If ComboBox1.SelectionLength > 0 Then
ComboBox1.Text = ComboBox1.Text
ComboBox1.SelectionLength = 0
ComboBox1.SelectionStart = ComboBox1.Text.Length
End If
End If
If Not IsTextKey(e.KeyCode) Then Exit Sub
Dim Filter As String = ComboBox1.Text & "*"
If Filter.Length = 1 Then Exit Sub
For I = 0 To ComboBox1.Items.Count - 1
If LCase(ComboBox1.Items(I).ToString) Like LCase(Filter) Then
ComboBox1.SelectedItem = ComboBox1.Items(I)
ComboBox1.Select(OriginalText.Length, (ComboBox1.Text.Length - OriginalText.Length))
Exit Sub
End If
Next
End Sub
Function IsTextKey(ByVal Key As Integer) As Boolean
Select Case True
Case Key = Keys.Up : Return False
Case Key = Keys.Down : Return False
Case Key = Keys.Left : Return False
Case Key = Keys.Right : Return False
Case Key = Keys.Back : Return False
Case Key = Keys.Delete : Return False
Case Key = Keys.LWin : Return False
Case Key = Keys.RWin : Return False
'add whatever I missed
'return false if the key either removes text from the textbox
'or does not produce a character
Case Else
'return true if the key produces a visible character(including space)
Return True
End Select
End Function
End Class
Private Sub ComboBox1_KeyUp(sender As System.Object, e As System.Windows.Forms.KeyEventArgs) Handles ComboBox1.KeyUp
If e.KeyCode = Keys.Enter Then
MessageBox.Show(ComboBox1.SelectedText)
Call SomeMethod()
End If
End Sub
I believe that you should set AutoCompleteMode to SuggestAppend and AutoCompleteSource to ListItems. This way, if what you type in is sustainable with the items loaded in the ComboBox, by writing it down and finding that item, when pressed Enter, the SelectedIndexChanged will be fired (even if a match wouldn't be found - the first in the list will be selected)
I've prepared something to point out this to you.
Regards,
Adi Konstantin
Subscribe to the KeyPressed event:
Private Sub yourComboBox_KeyPressed(sender As System.Object, e As System.KeyPressedEventArgs) Handles yourComboBox.KeyPressed
If e.KeyChar.Equals((char)Keys.Enter) Then
Call SomeMethod()
End If
this will helps your problems
Private Sub ComboBox1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles ComboBox1.KeyDown
If e.KeyCode = Keys.Enter Then
MsgBox("hello")'call some functions
End If
End Sub
Can you let me know if this works for you?
Private Sub ComboBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles ComboBox1.KeyPress
If e.KeyChar = Chr(13) Then
ComboBox1_SelectedIndexChanged(sender, e)
End If
End Sub
Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
MsgBox(ComboBox1.Text)
'Your code here
End Sub
I had a similar problem when the combobox dropdownstyle was set to simple with autocomplete set to append, sourcing from my listitems. My workaround was to have a string variable save the combobox text upon each textchanged event. That way, when ENTER is pressed, you can retrieve the deleted text and reassign it to the combobox text.
'Global declaration
'Global declaraion
dim selected_text as string = ""
Private Sub combobox_textchanged(sender As Object, e As EventArgs) Handles combobox.TextChanged
If combobox.Text IsNot Nothing And combobox.Text <> "" Then
selected_text = combobox.Text
End If
End Sub
Private Sub combobox_keydown(sender As Object, e As KeyEventArgs) Handles combobox.KeyDown
If e.KeyCode = Keys.Enter Then
combobox.Text = selected_text
'put logic here
End If
End Sub
There are some great answers above, but I liked that I didn't need to sort out all the command keys and arrows etc.
Close the list manualy on PreviewKeyDown event:
Private Sub cmbStatus_PreviewKeyDown(sender As ComboBox, e As PreviewKeyDownEventArgs) Handles cmbStatus.PreviewKeyDown
If e.KeyCode = Keys.Enter Then sender.DroppedDown = False
End Sub

Getting value of ListView using up / down keys

I need to store the value of ItemCode at coloumn 0 of my ListView.
Using the following code in click event, it works
vrEditProductCode = lvVendors.SelectedItems.Item(0).SubItems.Item(0).Text
But the same code in selectedindex changed event is causing an index out of range exception.
Please advise how to fix it. I want user to get this value when up/down arrow key is pressed.
In datagridview, we can do it like
vrItemCode=dgvOne.item(0,dgvitem.currentrow.index).value
But I could not do it in list view. Please help.
Thanks
What about this code snippet :
Private Sub ListView1_ItemSelectionChanged(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ListViewItemSelectionChangedEventArgs) Handles ListView1.ItemSelectionChanged
Debug.WriteLine(e.ItemIndex)
Debug.WriteLine(e.Item.Text)
End Sub
This should enable you to record items that have been selected.
I would recommend using the ItemSelectionChanged rather than the IndexChanged because it is more appropriate and easier to use, mainly because you get a more precise EventArg, specifically a System.Windows.Forms.ListViewItemSelectionChangedEventArgs
Because the ListView first deselects the old selection lvVendors.SelectedItems is null.
So you need to check first if SelectedItems != null:
VB.NET:
If lvVendors.SelectedItems IsNot Nothing AndAlso lvVendors.SelectedItems.Count <> 0 Then
Dim vrEditProductCode As String = lvVendors.SelectedItems.Item(0).SubItems.Item(0).Text
End If
C#:
if (lvVendors.SelectedItems != null && lvVendors.SelectedItems.Count!=0)
{
string vrEditProductCode = lvVendors.SelectedItems.Item[0].SubItems.Item[0].Text;
}
Maybe you can use this:
Private Sub lvSearch_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles lvSearch.KeyDown
If e.KeyCode = Keys.Down Then
If lvSearch.SelectedItems(0).Index < (lvSearch.Items.Count - 1) Then
txtName.Text = lvSearch.Items(lvSearch.SelectedItems(0).Index + 1).SubItems(1).Text
End If
End If
End Sub
Private Sub lvSearch_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles lvSearch.KeyUp
If e.KeyCode = Keys.Up Then
If lvSearch.SelectedItems(0).Index >= 0 Then
txtName.Text = lvSearch.Items(lvSearch.SelectedItems(0).Index).SubItems(1).Text
End If
End If
End Sub