Using VB.net (2005), I'm creating a custom control (a folder picker) that contains a textbox and button. Recently I've added the following:
<Browsable(True), DefaultValue(""), DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)> _
Public Overrides Property Text() As String
Get
Return Me.uiPath.Text
End Get
Set(ByVal value As String)
Me.uiPath.Text = value
End Set
End Property
The problem I'm having is that now when the control is created, the textbox always defaults to showing the name of the control (instead of being blank). It seems the Text property is being changed after Sub New is called, however, I've checked the designer, and I cannot see where it is doing this.
I know that changing the name of the property would resolve the issue, but I would like to know why this is happening (I'm guessing it has something to do with the standard designer?), and if there is a way to resolve (or work around) it, while still using the Text property?
I don't know if it makes any difference, but I am using a custom designer:
Public Class FolderPickerDesigner
Inherits Windows.Forms.Design.ControlDesigner
Public Overrides ReadOnly Property SnapLines() As IList
Get
Dim SnapLinesList As ArrayList = TryCast(MyBase.SnapLines, ArrayList)
If (Me.Control IsNot Nothing) AndAlso (Me.Control IsNot Nothing) Then
Dim FP As FolderPicker = CType(Me.Control, FolderPicker)
SnapLinesList.Add(New SnapLine(SnapLineType.Baseline, FP.uiPath.Bottom - 5, SnapLinePriority.Medium))
End If
Return SnapLinesList
End Get
End Property
End Class
Any help / ideas would be appreciated. If this doesn't / can't be resolved, I'll mark the most helpful post as the answer...
Set(ByVal value As String)
If Me.DesignMode And (Environment.StackTrace.Contains("System.Windows.Forms.Design.ControlDesigner.InitializeNewComponent")) Then Return
BaseT.Text = value
End Set
Related
Premise
Suppose that we have a class in a dll with a simple public property "OldP". In a newer version of this dll, I want to change the name of this property in "NewP". I can't simply replace the property name, because this dll is used in a lot of program and I can't change them...
I want to hide this property and show only the newer property. How is this possible?
"Browsable" attempt
Before asking this, I searched similar questions on StackOverflow and read something about Browsable, but it doesn't work. Here is my code:
Public Class Example
Private _p As Integer
<System.Obsolete("Use NewP instead", False)>
<System.ComponentModel.Browsable(False)>
Public Property OldP() As Integer
Get
Return _p
End Get
Set(ByVal value As Integer)
_p = value
End Set
End Property
Public Property NewP() As Integer
Get
Return _p
End Get
Set(ByVal value As Integer)
_p = value
End Set
End Property
End Class
When I create a new Example object, I can still see "OldP":
Where I'm wrong?
You cannot completely prevent the old property from being used, but you can hide it from IntelliSense by adding this directive: <System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)>. The OldP property will no longer be suggested, but still be accessible normally.
Beside that, I recommend you change the OldP property so that it refers not to the _p object, but to the NewP property to make future management easier, so that you don't have to worry about the deprecated version in the future.
First excuse my my english, I'm french.
I have made a control (a class in fact) inherited from textbox.
The purpose of this class is simply to keep the textbox aligned above a column of a datagridview.
All is working correctly. But I have a question :
I made a datagridview property, and in design time, I can simply select it in a combobox listing the datagridview of my form.
But I have also a columnName property as a string. I would like that, once the datagridview is selected, the designer propose me the list of the datagridviewcolumn name in this property.
I have absolutly no idea how to achieve that. I'm a very beginner in code, and have made no studies on it.
I tried making the string property into a datagridviewcolumn property, but not only did the designer do not propose me the ones available, but also it crashes and I have to remove all about this textbox in the file.Designer.vb.
Thank you for your help.
EDIT : Here is the code :
Public Class TextBoxFilter
Inherits TextBox
Private WithEvents _DGV As DataGridView = Nothing
Public Property DGV As DataGridView
Get
Return _DGV
End Get
Set(value As DataGridView)
_DGV = value
End Set
End Property
Private _ColumnName As String = String.Empty
Public Property ColumnName As String
Get
Return _ColumnName
End Get
Set(value As String)
_ColumnName = value
End Set
End Property
The rest of the code is irrelevant. Just know that it features event (when datagridviewcolumns are move, not displayed, not visible) to adjust the textbox.
To answer Plutonix, I would like to be able to give the designer a list of column, even if there is several datagridview in the form, and even if it can't find them automatically. I suppose I could do that in the set of the datagridview ? But I don't know how.
I´m devoloment my own userControl with vb.net. I´m new with this task.
I want to remove default properties.
After google, I found several topics, like this:
Removing certain properties in a user control, i.e. forcing one value and not editable in Design mode
So, I´m trying to use it, but doesn´t works for me. I don´t know what I missing or doing wrong.
Public Class MyControlDesigner
Inherits System.Windows.Forms.Design.ControlDesigner
Protected Overrides Sub PreFilterProperties(ByVal properties As System.Collections.IDictionary)
MyBase.PreFilterProperties(properties)
properties.Remove("BackColor")
properties.Remove("ForeColor")
properties.Remove("Font")
End Sub
End Class
<DesignerAttribute(GetType(MyControlDesigner))> _
Public Class MyUserControl
' ...
End Class
To hide overwrite properties I follow this topic Hiding inherited properties and this works fine, for some of them.
<Browsable(False), EditorBrowsable(EditorBrowsableState.Never)> _
Public Shadows Property AutoScroll() As Boolean
Get
Return m_AutoScroll
End Get
Set(ByVal value As Boolean)
m_AutoScroll = value
End Set
End Property
But still, I have other properties that I don´t know how to hide or remove. Like Font, ForeColor, Margin etc...
Thanks advanced
Edit: Once I finish my control, I don´t want to see, all the properties like the picture, Only I want to show mine´s.
Edit: Add code from #Plutonix
I do not have access to that control/tool/property editor, but you can try to use a TypeConverter. This works with a control that inherits from UserControl to hide properties from a Property Grid, but it wont hide them from the VS IDE property editor.
The VS IDE uses reflection to get the property list and apparently ignores the TypeConverter. If your tool does something similar, this wont work - again, I dont have the tool to test it, but it is simple and worth a try.
I created an actual UserControl with a few controls on it. Then:
Imports System.ComponentModel
Public Class YControlConverter
Inherits TypeConverter
Public Overrides Function GetPropertiesSupported(context As ITypeDescriptorContext) As Boolean
Return True
End Function
Public Overrides Function GetProperties(context As ITypeDescriptorContext,
value As Object,
attributes() As Attribute) As PropertyDescriptorCollection
Dim propNames() As String = {"backcolor", "forecolor",
"autoscroll", "autoscrollminsize",
"autoscrollmargin", "autoscrolloffset",
"autoscrollposition"}
Dim pdc As PropertyDescriptorCollection = TypeDescriptor.GetProperties(context.Instance)
' collection to store the ones we want:
Dim myPDCList As New List(Of PropertyDescriptor)
For Each pd As PropertyDescriptor In pdc
If propNames.Contains(pd.Name.ToLowerInvariant) = False Then
myPDCList.Add(pd)
End If
Next
Return New PropertyDescriptorCollection(myPDCList.ToArray())
End Function
End Class
Then decorate your usercontrol with the TypeConverter:
<TypeConverter(GetType(YControlConverter))>
Public Class YControl
This basically runs thru the PropertyDescriptorCollection for the control and filters out the unwanted properties before returning the new collection. If it works, just add the names to the propNames array that you want to hide. View in a PropertyGrid:
As you can see, all the AutoScroll... properties are removed as well as BackColor. The others are gone as well. If the editor will use your TypeConverter instead of reflection, it should work.
--
How to test your TypeConverter using a PropertyGrid. Using a form with a property grid and a button, in the button click:
Dim yp As New YControl
PropertyGrid1.SelectedObject = yp
If the AutoScroll... properties are missing from the prop grid, your TypeConverter works! If they still show in the other tool, it is using reflection like VS.
I'm trying to assign text from "comp" in the form "home" to a textbox with the name "d1" in the form "home".
but this needs to be done with a counter in the form "home".
The code is in a module.
What I've tried=
home.controls("d" & home.counter).text = home.comp.text
I keep getting an error:
use the new keyword to create an object instance ==> the textbox exists in the form
check to determine if the object is null before calling the method ==> the textbox is empty
get general help for this exception
You could use Controls.Find:
Dim controls = home.Controls.Find("d" & home.counter, True)
If controls.Length > 0 Then
Dim txt = TryCast(controls(0), TextBoxBase)
If txt IsNot Nothing Then
txt.Text = home.comp.text
End If
End If
However, normally i would not use this approach since it's error-prone. Why don't you provide a public property in the Home-form that you can access? This property would get/set the TextBox' Text.
For example:
Public Property HomeCompText As String
Get
Return txtHomeComp.Text
End Get
Set(value As String)
txtHomeComp.Text = value
End Set
End Property
Now you can use this clear, safe and maintainable code:
home.HomeCompText = home.comp.text
You could even change the underlying control.
I'm trying to create a new property with a type of StringDictionary but when I use the property like a stringdictionary variable I am getting an error.
The goal is to NOT use a variable, I need to use a property for this. Behind the scenes I am saving the stringdictionary value to a global user-ID indexed collection. Here's the code that creates the property and attempts to get and set:
Public Property MaxLenDict As StringDictionary()
Get
Return GetFromCollection("MaxLenDict")
End Get
Set(Value As StringDictionary())
SaveToCollection("MaxLenDict", Value)
End Set
End Property
Public Sub ExampleSub()
If MaxLenDict("hello world") = "" Then MaxLenDict.Add("Hello World", "I'm Here")
End Sub
Get this error in ExampleSub "StringDictionary cannot be converted to string" in the IF statement on this code:
MaxLenDict("hello world")=""
So how do I successfully make and use a property as a stringdictionary?
Your property is of type StringDictionary() (an array!), not StringDictionary.
I’m not sure that using StringDictionary is advised in the first place, though. The class is simply a remnant from pre-generics versions of .NET. Use Dictionary(Of String, String) instead.