I'm working on a windows form app containing a TabControl. In one of the TabPages I have a GroupBox that contains a FlowLayoutPanel. I also have a SQL database table containing user notes/comments. Upon form load, I use a SqlDataReader to populate a user control for each note (creation date, note text, username, etc.). The FlowLayoutPanel then gets filled by UserControls. However, I would like for the user to be able to select individual notes/UserControls for editing/deleting. I was initially using a DataGridView instead of UserControls, but notes vary in length and the DataGridView didn't look very organized. My UserControl contains a self-expanding RichTextBox. I thought about adding CheckBoxes next to each UserControl, but I'm not sure how to track which box belongs to which UserControl. Is there a smarter way to accomplish this?
This is a url for a screenshot of the UserControl: https://imgur.com/a/ZN7MM
(I don't have enough reputation to post images.)
And here is the code I got from another post on the self-expanding richtextbox:
Private Sub RichTextBox1_ContentsResized(sender As Object, e As ContentsResizedEventArgs) Handles rtbNote.ContentsResized
rtbNote.Height = e.NewRectangle.Height + 10
End Sub
Related
I have a TextBox nested inside a TabControl.
Form->TabControl1->TabPage1->TabControl2->TabpPage2->GroupBox->TextBox
When the TabPage1, TabPage2 is selected, so the TextBox is visible to the user all the TextBoxEvents works OK, but when the user selects another TabPage it doesn't work.
I have a timer that send data periodically to know if an external device is present on a specific virtual COM port.
When the external device answer I put that data in that TextBox and set a global flag(boolean) to let the rest of the program that a device is present.
I'm processing the received data on a Private Sub and changing that TextBox with a Lambda expression like this
Me.Invoke(Sub()
Me.VersionFirmwareTxt.Text = RespX.Substring(5)
End Sub)
You can access the TextBox by name from anywhere whether it is visible or not, via casting (CType), and update its text value using the syntax:
'(from within the same Form, e.g., Form1)
CType(TabControl1.TabPages(1).Controls("VersionFirmwareTxt"), TextBox).Text = RespX.Substring(5)
'(from a different Form)
CType(Form1.TabControl1.TabPages(1).Controls("VersionFirmwareTxt"), TextBox).Text = RespX.Substring(5)
If you dynamically added the TextBox to the controls of the parent (TabPage), you will know exactly where the TextBox is located, since you would have already used, e.g.:
TabControl1.TabPages(1).Controls.Add(VersionFirmwareTxt)
Whereas if you manually added the TextBox to the TabPage, you also know the parent control.
I have a vb.net form that uses multiple textboxes across several different tabs. Within one of those tabs, I have a sub set of tabs. My save functionality calls stored procs for each tab and cycles through the values on each page to either do an update or a "add new". I noticed that while testing, some of the pages do not save or update any of the values in the textboxes. After a few days of investigating, I realized that if I edit something, then physically click through the other tabs, it all saves/updates properly. If I don't click through them, they don't all save. Is there a reason for this that I am missing? When you enter a search value, I cycle through the pages and populate them all at the same time so I was assuming it wrote those values BEFORE it physically rendered...I guess I am wrong?
From the TabPage documentation Remarks section
Controls contained in a TabPage are not created until the tab page is shown, and any data bindings in these controls are not activated until the tab page is shown.
So the answer to your question is "Yes the tabpage must be shown".
However, the definition of "shown" is subject to interpretation. In reality, all you need to do set the TabPage.Visible property to True and not actually cycle through and display each TabPage.
A recursive scan of the form for TabPage controls will work:
Private Shared Sub TabPagesVisible(parent As Control)
For Each c As Control In parent.Controls
If TypeOf c Is TabPage Then c.Visible = True
TabPagesVisible(c)
Next
End Sub
Example usage:
Sub SaveFormTabData()
TabPagesVisible(Me) ' Me refers to the containing form
' code to save control data
End Sub
Currently I have a program that is able to write to a ListView with column named : number, time, description . This listview is not bound to anything data, I'm just basically writing into it using the code.
What I want to do is to have a TextBox, whereby if the user wants to look at particular number i.e. 2, when they type into the textbox, then I want the listview to only show data with number = 2. When there's nothing in the textbox, I want the listview to show all the data.
I have being looking around on the internet and I didn't seem to find a filter method. Does it even exist and if so how would I go about implementing this.
All help is appreciated.
While I recommend using a DataGridView with DataSource but in cases that you need to use ListView, you can use this solution.
You can filter your list view this way:
Define a member field as backup storage of items:
In form Load after adding items to list view, store each item in that member field
Put a TextBox and a Button on form and handle Click event of the Button and in the handler, first clear all items of ListView then each item from that backup storage that matches with criteria.
Member Field for Backup of Items
Private ItemsBackup As New List(Of ListViewItem)
Fill backup after loading items in ListView in the form Load event
For Each item As ListViewItem In ListView1.Items
ItemsBackup.Add(item)
Next
Code of Filter
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Me.ListView1.BeginUpdate()
Me.ListView1.Items.Clear()
For Each item As ListViewItem In ItemsBackup
If (item.Text = Me.TextBox1.Text Or String.IsNullOrEmpty(Me.TextBox1.Text)) Then
Me.ListView1.Items.Add(item)
End If
Next
Me.ListView1.EndUpdate()
End Sub
You can also use above code for TextChanged event of the TextBox.
Here is a test data:
For i = 1 To 30
Dim item As New ListViewItem(i.ToString())
item.SubItems.Add(DateTime.Now.AddHours(i))
Me.ListView1.Items.Add(item)
Next
A normal .NET ListView can't do this without a considerable amount of work. So, you could use ObjectListView -- an open source wrapper around a standard .NET ListView -- which has already done all the work for you.
It has built-in filtering (and highlighting)
Apologies in advance for the long-winded post, but I'm having some trouble with a .NET page I'm building.
END QUESTION: How can I check the 'Checked' property of a dynamically-created checkbox during the Page_Load subroutine?
DETAILS: Basically, I have a VB.NET page that creates some table rows dynamically, based on a number selected by the user. So, for example, if the user selects "3" from a dropdown list, the page posts back and creates three table rows. Each row contains a couple of textboxes, a dropdown list, and a checkbox (which are all .NET form controls rather than plain HTML controls, I should point out).
Typically, the user would enter a few details into the form controls, and click the 'Submit' button, after which the page iterates through each row, and inserts the data into a SQL Server table.
But if the user ticks the checkbox for that row, this signifies that the page is to ignore that row, and NOT insert that row of data into the database when the user clicks 'Submit'.
This works well, but there is a problem. If the user clicks 'Submit' and some of the values entered into the form controls are invalid (so, for example, the user didn't enter their name) then the page won't submit the data, and instead, shows an error to the user informing them of the values they need to change. But if the user creates three rows, for example, but decides to "ignore" the third row (by ticking the checkbox) then when the page posts back, finds some invalid entries, and re-shows the form to the user to allow them to correct any errors, I'd rather the page didn't render the third row altogether. After all, they chose to create three rows originally, but then decided that they only needed two. So it makes sense that the third row is not recreated.
To start with, I simply used code similar to the following within my Page_Load subroutine:
If objCheckbox.Checked = False
' Render the row, and recreate the dynamic controls '
Else
' Dont render the row or any of the controls '
End If
But what seemed to happen was that objCheckbox.Checked was always returning False, even when the checkbox was ticked. Once the page had loaded, the table rows had rendered again, and the tick was present in the checkbox, so it's not like the value was lost on postback. But at the point I check whether the checkbox is ticked, it always returns False, rendering a table row that the user doesn't need.
Does anyone know how to get round this problem? I've read lots of articles about the .NET ViewState, and the page lifecycle, but I've yet to find a solution that works. I simply need to be able to check if a checkbox is ticked before re-creating some dynamic controls.
I tried this alternative code, which utilises the ViewState, but to no avail:
If objIgnoreCheckbox.ViewState("Checked") = False Then
' Render the row, and recreate the dynamic controls '
Else
' Dont render the row or any of the controls '
End If
When doing this, I get the following error:
'System.Web.UI.Control.Protected Overridable ReadOnly Property ViewState() As System.Web.UI.StateBag' is not accessible in this context because it is 'Protected'.
So I tried to create a custom class, that inherited from Checkbox, and tried to override the ViewState property to make it public, so that it can be read from:
Public Class CheckboxControl
' Inherits all Checkbox properties and methods '
Inherits Checkbox
' Create the public ViewState property '
Public Overrides ReadOnly Property ViewState As StateBag
Get
Dim objChecked As Object = ViewState("Checked")
If Not (IsNothing(objChecked)) Then
Return objChecked
End If
End Get
End Property
End Class
But then I basically found out that you can't override a protected member with a public one. I've had very little experience with creating new classes etc, so I'm stumped.
So if anyone can tell me how to go about checking the darned checkbox, I'd be eternally grateful! I've spent a full working day trying to solve the problem, but with no luck!
Thanks in advance!
For static controls, the view state of controls is restored in Page_Init, which happens before Page_Load, so they contain the correct values in Page_Load. Dynamic controls are created in Page_Load, so their viewstate is incorrect in Page_Load and will be restored after Page_Load, but before calling event handlers. MSDN says:
After the Page_Load event has run, but before control event-handling methods are called, the remaining view state information is loaded into the dynamically created controls.
This is why Checked returns false, and why changing the visibility of CheckBox.ViewState will not solve your problem.
Solution (untested, but I think it should work): Create all controls (even those that you don't want to display) in Page_Load. Attach an event handler on CheckedChanged to your CheckBoxes (in Page_Load). After Page_Load has finished, ASP.NET will restore the view state of the newly created controls (that's why it is important to create the same controls in Page_Load, so that ASP.NET can correctly map the view state to the control), and ASP.NET will call your event handler for those CheckBoxes that have been changed. There, you can remove the rows you don't want to display.
This is how you add the event handler
AddHandler objCheckbox.CheckedChanged, AddressOf MyCheckedChangedFunction
This function would look something like this:
Function MyCheckedChangedFunction(sender As Object, e As EventArgs)
Dim objCheckbox = DirectCast(sender, CheckBox)
... access objCheckbox.Changed and do something useful here ...
End Function
I'm currently creating a WinForm in VB.NET bound to an access database.
Basically what i have are two forms: one is a search form used to search the database, and the other is a details form. You run a search on the searchForm and it returns a list of Primary Keys and a few other identifying values. You then double click on the entry you want to view, and it loads the details form.
The Details form has a collection of databound controls to display the data: mostly text boxes and checkboxs. The way i've set it up is i used the UI to build the form and then set the DataBindings Property of each control to "TblPropertiesBindingSource - " where value name is one of the values in the table (such as PropertyID or HasWoodFloor).
Then, when you double click an entry in the searchform, I handle the event by parsing the Primary Key (PropertyID) out of the selected row and then storing this to the details form:
Note: Detail is the details form that is opened to display the info
Private Sub propView_CellDoubleClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles propView.CellDoubleClick
Dim detail As frmPropertiesDetail = New frmPropertiesDetail
detail.id = propView.Rows(e.RowIndex).Cells(0).Value
detail.Show()
End Sub
Then, upon loading the details form, it set's the filter on the BindSource as such:
TblPropertiesBindingSource.Filter() = "PropertyID=" & id
This works great so far. All the controls on the details form will display the correct info. The problem is updating changes.
Scenario:
If i have the user load the details for say, property 10001, it will show a description in a textBox named descriptionBox which is identical to the value of the description value of for that entry in the database. I want the user to then be able to change the text of the text box (which they can currently do) and click the save button (saveBut) and have the form update all the values in the controls to the database.
Theorectically, it should do this as the controls are DataBound, thus i can avoid writing code that tells each entry in the database row to take the value of the aligned control.
I've tried calleding PropertiesTableAdapter.Update(PropertiesBindingSource.DataSource), but that doesnt seem to do it.
Ok, I was able to figure this out picking apart some code I pillaged from a friend.
Everything was ok, the problem was the updating
When I was saving the data, i was calling just:
Me.TblProptertiesTableAdapter.Update(Me.TblPropertiesBindingSource.DataSource)
The correct code, without changing anything else is:
Me.Validate()
Me.TblPropertiesBindingSource.EndEdit()
Me.TblPropertiesTableAdapter.Update(Me.RentalPropertiesDataSet.tblProperties)
Me.RentalPropertiesDataSet.AcceptChanges()
Where RentalPropertiesDataSet is the database where TblProperties comes from. Inorder for this to work, make sure TblPropertiesBindingSource.DataSource is RentalPropertiesDataSet.Properties This was autosetup for me by VS08 when it created the BindingSource.
Basically, I needed to tell teh BindingSource to stop allowing the fields to be edited. Then we save the changes to the database, and lastly we tell the DataBase to accept the changes.