I have to build a graph digitizer to make the user have a graph by points from an image. This could be an example of an imported graph
What I'd like is that the user graphically defines, at first, the X axis domain (in the picture from 0 to 2000) and the Y axis domain (in the picture from 0 to 180) and then picks some points on the curve and, once this procedure has ended, I need to have the points added to a Datagridview that I've already done. Could anyone suggest me where to start?
Edit: I've set the way to store the mouse position, when the mouse button is pressed:
Private Sub PictureBox1_MouseClick(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseClick
If PictureBox1.Image IsNot Nothing Then
Form3.ListBox1.Items.Add(e.X)
End If
End Sub
I need to activate this sub when I press a specified button. Until I press the button, the mouse position, even if clicking inside the picturebox, must not be stored. If tried to put the picturebox sub inside the Button_click sub but It doesn't work.
Another event that I have to program is that - when pressing the mouse button inside the picturebox - on the first click, Form4 must be shown; at the second click, Form5 must be shown; at the third click, Form6 must be shown. From the fourth click (until the user has ended to pick points), the mouse position must be stored.
Related
I have the following code:
Private Sub btnNew_Click(sender As Object, e As EventArgs) Handles btnNew.Click
Dim f As New frmStyle
f.ShowDialog()
End Sub
frmStyle does many things during it's Load event, so it doesn't appear immediately. Instead, it takes around 1 second to show up.
Because of that, I want to show an hourglass cursor during the form's Load event.
In VB6 it was super easy. I could just use "Screen.Cursor = vbHourglass".
Then you could set the cursor back to the default from whereever you wanted, for example at the end of a Form_Load event.
How can this be done in VB.NET now?
I want to show the cursor application-wide, and not for a single control only.
And ALSO (what makes my question unique and NOT answered so far in another question), I need to reset it, but it should be reset at the end of Form_Load (which is NOT the initializing element. Instead the button is the "initializing" element, but I can not set the cursor to default at the end of the button click because ShowDialog is shown modally. This means that the cursor would only be changed back if the form was closed again).
Thank you!
I have a DataGridView control on a TabPage of a Windows Form application.
When the user moves the mouse over the DataGrid and uses the scroll wheel, the grid scrolls as expected. But when the user clicks in a cell on the screen, instead of the cell receiving focus, the DataGrid resets to the top and requires the user to scroll down again. This response is non-intuitive since it's not immediately obvious that the cell you thought you clicked on isn't there anymore.
I would be happy to prevent the DataGrid from responding to the scroll wheel until the user clicks in the grid, or preferably to maintain the current actions except not resetting to the top when first clicked.
From what I've researched here, it appears that the DataGrid is rebinding because I'm resetting the binding when the tabpage is entered (since the database might have been updated by one of the other tabs.
Private Sub TabPage1_Enter(sender As Object, e As EventArgs) Handles TabPage1.Enter
LoadTACTable()
End Sub
In LoadTACTable():
dbGetList("spSelectTACList", dtTACs, 0, 100000, Nothing) ' Record numbers are 0 based
bsTACs.DataSource = dtTACs
With gridTACs
' TOTAL Grid width = 1380
.DataSource() = bsTACs
.
.
.
(Showing only part of the code for brevity.
Is there a way to see if the TabPage is already displayed when entered? Or, is unnecessary to reset the gridTAC datasource every time I retrieve the data from the SQL database to the dtTACs datatable using my dbGetList() sub?
There are several possible solutions to your problem. One would be to not automatically rebind the datagrid but let the user do it by clicking some refresh button. That way the user would not see non-intuitive behavior.
You mentioned that the contents of one tab may need to be refreshed when the contents of other tabs are changed. Whenever the contents of a tab is changed and can affect other tabs, you could flag these other tabs (for example, by adding a star to their titles) to indicate that they no longer have the latest data. The user would then know that the tab needs to be refreshed.
There might be other solutions, but it is difficult to tell without knowing more about your use case.
With the guidance above, I believe I solved the issue:
I created a flag:
Dim TabDirty As Boolean
Then I set it in the TabPage.Leave handler:
Private Sub TabPage1_Leave(sender As Object, e As EventArgs) Handles TabPage1.Leave
dtTACs.Dispose()
TabDirty = True
End Sub
Then I just check it when I enter the TabPage:
Private Sub TabPage1_Enter(sender As Object, e As EventArgs) Handles TabPage1.Enter
If TabDirty = True Then
TabDirty = False
LoadTACTable()
End If
End Sub
So far, this appears to work - the grid is not getting reset when clicked, but I will do a bit more testing to confirm that the data is refreshed when necessary.
I have a DataGridViewButtonCell in my DataGridView and I wanted to set the property Visible to True.
I have tried:
DataGridView1.Rows("number of row i want").Cells("number of cell i want").Visible = True
Unfortunately it says that the property visible is read only.
Here is the code:
Private Sub DataGridView1_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellClick
'does not work
DataGridView1.Rows(e.RowIndex).Cells(6).Visible = True
End Sub
Does anyone knows how I can achieve this?
Thanks.
There is no actual way to hide a DataGridViewButtonCell. Currently I can only see two options:
Use padding to move the button over as shown here. I will provide similar VB.NET code
Set the Cell to a DataGridViewTextBoxCell and set the ReadOnly property to True
Use Padding:
Private Sub DataGridView1_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellClick
If DataGridView1.Rows(e.RowIndex).Cells(6).GetType() Is GetType(DataGridViewButtonCell) Then
Dim columnWidth As Integer = DataGridView1.Columns(e.ColumnIndex).Width
Dim newDataGridViewCellStyle As New DataGridViewCellStyle With {.Padding = New Padding(columnWidth + 1, 0, 0, 0)}
DataGridView1.Rows(e.RowIndex).Cells(6).Style = newDataGridViewCellStyle
End If
End Sub
Use DataGridViewTextBoxCell:
Private Sub DataGridView1_CellClick(sender As Object, e As DataGridViewCellEventArgs) Handles DataGridView1.CellClick
If DataGridView1.Rows(e.RowIndex).Cells(6).GetType() Is GetType(DataGridViewButtonCell) Then
Dim newDataGridViewCell As New DataGridViewTextBoxCell
DataGridView1.Rows(e.RowIndex).Cells(6) = newDataGridViewCell
newDataGridViewCell.ReadOnly = True
End If
End Sub
Both of these should give you the effect of not showing the button.
This is really a perspective issue. From a programmer’s perspective, simply ignoring the button clicks on the buttons I want to disable is very easy to do and takes just a few lines of code.
From a user perspective, this situation would play out like this… the user clicks what appears to be a valid enabled button, and nothing happens. The user did not write the code for this… so at best the user will think the computer is not responding to the button click or at the worst… would think your coding skills are dubious!
The same situation happens if the button is missing. The user is not going to know why it is missing… but will most likely come to the same conclusion described above with a non-working button.
In another very simple approach, let say that all the buttons are enabled and we have a list of the button indexes we want to disable. The users presses one of the buttons, we check the disabled button list and if the clicked button is one that is disabled, simply display a message box to indicate why this button is disabled. This approach says to the user… “Here are a bunch of buttons, guess which ones are enabled”…
The DataGridViewDisableButtonCell and DataGridViewDisableButtonColumn wrappers solve all of the above issues… the button is visible so the user wont question where the button went if you set it to invisible and it is greyed out. “Greyed out” is something most users understand and will relieve the user of having to “guess” which buttons are enabled.
You can create a wrapper for two classes: the DataGridViewButtonCell and the DataGridViewButtonColumn.
The link How to: Disable Buttons in a Button Column in the Windows Forms DataGridView Control to the MS example is one I have used before using C#, however there is a VB implementation at the link also.
Below is a picture of the result of using the two wrappers described in the MS link. For testing, the picture below uses the check boxes to left of the button to disable the button on the right.
IMHO, using this strategy is user friendly. If you simply make the button invisible or read only, then the user is possibly going to think your code is messed up and not have a clear understanding of WHY the button is missing or doesn’t work. A disabled button indicates to the user that the button is not available for that item. An option would be to have a mouse roll-over indicating why the button is disabled.
I am working on a tool that docks primarily in the system tray. However, if the icon is clicked, the form opens for more options displayed on the form. (Not a context menu) However, I want to position the form directly above the system tray and have no clue how to go about doing this. This application will run on multiple user computers with varying screen resolutions, so hard coding a preset coordinate is not a viable solution.
I did search for FindWindow() for the system tray but could not find anything useful out of Google/Bing.
There is a Screen.WorkingArea property which allows you to get the primary screen "available resolution".
Just put your window top at working area height - window height and window left at working area width - window width (and adjust if necessary to get a bit of margin).
Update: Also, account for the taskbar position and size: How do I get the taskbar's position and size?
You could use this:
First Set The form TopMost
MyForm.TopMost = True
To show the form on top of taskbar on right side, here is example:
Private Sub SetFormPosition()
Dim leftpos As Long
Dim toppos As Long
leftpos = (My.Computer.Screen.WorkingArea.Right - 2) - Me.Width
toppos = (My.Computer.Screen.WorkingArea.Bottom - 2) - Me.Height
Me.Location = New Point(leftpos, toppos)
End Sub
You can play around and change Values. (-2) is close to edge, if you put bigger number you will be away from the edge and so on. You can also change the My.Computer.Screen.WorkingArea where you want to show the Form.
You can use the code on NotifyIcon_MouseClick Event
Private Sub NotifyIcon_MouseClick(sender As Object, e As System.Windows.Forms.MouseEventArgs) Handles NotifyIcon.MouseClick
If e.Button = Windows.Forms.MouseButtons.Left Then
SetFormPosition()
MyForm.Show()
End If
End Sub
I have a form that has two views. These views are controlled by radio buttons on top of the form.
Here is the program:
http://dl.dropbox.com/u/41629841/DataCalculator/DataCalc1.PNG
Notice how the Radio button for Number Converter is selected.
Here is what it looks like when you select the Text Converter radio button:
http://dl.dropbox.com/u/41629841/DataCalculator/DataCalc2.PNG
That isn't right. I have it set to hide the panel containing the number converter and show the one containing the text converter when you click that one. It hides the number converter but doesn't show the text converter.
Here is a picture of the text converter panel:
http://dl.dropbox.com/u/41629841/DataCalculator/DataCalc4.PNG
Here is the relevant code:
Private Sub frmCalculator_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
rdoNumberConverter.Checked = True
End Sub
Private Sub rdoTextConverter_Click(sender As Object, e As System.EventArgs) Handles rdoTextConverter.Click
pnlTextConverter.Visible = True
pnlNumberConverter.Visible = False
End Sub
Private Sub rdoNumberConverter_Click(sender As Object, e As System.EventArgs) Handles rdoNumberConverter.Click
pnlNumberConverter.Visible = True
pnlTextConverter.Visible = False
End Sub
Everything seems right and I can't figure out why the text converter doesn't show up. I've determined that it has something to do with the fact that both of the panels are right on top of each other because when I move them apart, the visibility toggling works perfectly.
Here are the supporting pictures:
http://dl.dropbox.com/u/41629841/DataCalculator/DataCalc5.PNG
http://dl.dropbox.com/u/41629841/DataCalculator/DataCalc6.PNG
So how do I make it work when they are on top of each other?
I tried using BringToFront() and SendToBack() to make sure the visible panel is in the front and it didn't make a difference.
Make sure the TextConverter panel isn't "inside" the NumberConverter panel.
From the designer, move them into different places so that they do not overlap at all.
Then in code, move them into place:
textConverterPanel.Location = numConvertPanel.Location
Your visible, not visible toggling should work then.
The issue is the panels becoming embedded, as pointed out by #LarsTech. This occurs if you use the GUI to move them to the same location.
If you want to overlap them at design time, create the second panel in a different location. Then in the Properties of the panel in the final location, copy the Location, and paste it into the Location property of the second panel. This will move it to the proper location in the Designer without embedding one into another. This can be repeated for as many additional panels as needed.