I'm programming in a MVVM pattern and I have problems using textbox values in my function. When I call my function it does not use the values the user entered in the textbox. It is just empty. I looks like it inherits empty fields and just skips the filled in textbox fields. Please take a look at my code here
I call the addUser function from the AccountAddView here
Public Class AccountaddView
Public Sub btnAccountAdd_Click(sender As Object, e As RoutedEventArgs) Handles btnAccountAdd.Click
If txtPasswordAdd.Password <> txtPasswordAdd2.Password Then
warningLabel.Visibility = Visibility.Visible
Else
Dim model = New AccountaddModel()
model.addUser()
The functions triggers the Model
Public Class AccountaddModel
Inherits AccountaddViewModel
Public Function addUser()
Dim url As String = "https://azurefunctionsmywebsite" + "&name=" + username + "&pass=" + pass + "&role=" + role
Dim request As WebRequest = WebRequest.Create(url)
Dim response As WebResponse = request.GetResponse()
Dim result As String = New StreamReader(response.GetResponseStream()).ReadToEnd()
End Function
End Class
As you can see the Model inherits from the AccountAddViewModel. This class stores the variables that the user filled in the textbox
Public Class AccountaddViewModel
Inherits AccountaddView
Public username As String = txtUsernameAdd.Text
Public pass As String = txtPasswordAdd.Password
Public role As String = txtProjectrolAdd.Text
End Class
I have no errors. When I fill in the username,pass and role as an user the URL in the function does not fill it with the data. It is just empty.
I hope someone can help me out with this inheritance issue.
Related
I have a populated listbox. Each item has a string of data with id's and values. How would i search for the id and receive the vale?
If i search for 'itemColor' i would like it to return each boot color in a new msgbox.
itemName="boots" itemCost="$39" itemColor="red"
itemName="boots" itemCost="$39" itemColor="green"
itemName="boots" itemCost="$39" itemColor="blue"
itemName="boots" itemCost="$39" itemColor="yellow"
I understand there are different and easier ways to do this but i need to do it this way.
Thanks!
Here's one way to do it involving parsing the text as XML:
' Here's Some Sample Text
Dim listboxText As String = "itemName=""boots"" itemCost=""$39"" itemColor=""red"""
' Load XML and Convert to an Object
Dim xmlDocument As New System.Xml.XmlDocument
xmlDocument.LoadXml("<item " & listboxText & "></item>")
Dim item = New With {.ItemName = xmlDocument.DocumentElement.Attributes("itemName").Value,
.ItemCost = xmlDocument.DocumentElement.Attributes("itemCost").Value,
.ItemColor = xmlDocument.DocumentElement.Attributes("itemColor").Value}
' Write It Out as a Test
Console.WriteLine(item.ItemName & " " & item.ItemCost & item.ItemColor)
Console.Read()
Create a class (or structure), the appropriate properties, a default constructor, a parametized constructor and an Override of .ToString.
Public Class Item
Public Property Name As String
Public Property Cost As String
Public Property Color As String
Public Sub New()
End Sub
Public Sub New(sName As String, sCost As String, sColor As String)
Name = sName
Cost = sCost
Color = sColor
End Sub
Public Overrides Function ToString() As String
Return $"{Name} - {Cost} - {Color}"
End Function
End Class
Item objects are added to the list box calling the parameterized constructor. The list box calls .ToString on the objects to determine what to display.
Private Sub FillList()
ListBox3.Items.Add(New Item("boots", "$39", "red"))
ListBox3.Items.Add(New Item("boots", "$39", "green"))
ListBox3.Items.Add(New Item("boots", "$39", "blue"))
ListBox3.Items.Add(New Item("boots", "$39", "yellow"))
End Sub
Since we added Item objects to the list box, we can cast each list item back to the Item type and access its properties.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim sb As New StringBuilder
For Each i In ListBox3.Items
sb.AppendLine(DirectCast(i, Item).Color)
Next
MessageBox.Show(sb.ToString)
End Sub
I'm making a "Preference form" that will hold all the users preferences and when they go to Apply/Save I want the new values to transfer back to the main form and updateand close the form2. In the past I have done this like this:
Private Sub PreferencesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles PreferencesToolStripMenuItem.Click
Preferences.Show()
End Sub
and when I click the "Apply/Save" button before it closes I would Transfer all data like this:
form1.textbox.text = form2.textbox.text
Is there anything wrong doing it this way??
What I have been reading is I should be doing it like this:
Private Sub PreferencesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles PreferencesToolStripMenuItem.Click
Dim dialog As New Preferences
dialog.ShowDialog()
End Sub
And when when they click "Apply/Save" it would take all the values from Form2 and store them in a private variable (or Property) in Form2 and when that form closes I would then access the value like this:
Private Sub PreferencesToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles PreferencesToolStripMenuItem.Click
Dim dialog As New Preferences
dialog.ShowDialog()
form1.textbox.text = dialog.variable
End Sub
Why would this be a better way of doing this?
UPDATE....Looking at the code below this is just a SMALL sample of all the options I will have. What is the best way to collect of the data into the object to use when serializing?
<Serializable>
Public Class Preference
#Region "Properties"
Public Property ScaleLowest As String = "5"
Public Property ScaleHighest As String = "200"
Public Property ScaleInc As String = "5"
Public Property ThickLowest As Double = 0.125
Public Property ThickHighest As Double = 4
Public Property ThickInc As Double = 0.125
Public Property WidthLowest As Double = 0.125
Public Property WidthHighest As Double = 0.6
Public Property WidthInc As Double = 0.125
Public Property LengthLowest As Double = 1
Public Property LengthHighest As Double = 96
Public Property LengthInc As Double = 1
Public Property FractionON As Boolean = False
Public Property DecimalON As Boolean = True
Public Property ColorSelection As String = "Colors"
Public Property FinalColor As String = "255, 255, 0"
Public Property roughColor As String = "255, 255, 100"
Public Property SplashON As Boolean = False
Public Property LogInON As Boolean = False
#End Region
Public Sub New()
'for creating new instance for deserializing
End Sub
Public Sub GatherAllData()
'Save Defaults
SaveSerializeObj()
End Sub
Public Sub SaveSerializeObj()
'Get Changes?????
'Serialize object to a text file.
Dim objStreamWriter As New StreamWriter("C:\Users\Zach454\Desktop\test.xml")
Dim x As New XmlSerializer(Me.GetType)
x.Serialize(objStreamWriter, Me)
objStreamWriter.Close()
End Sub
Public Function LoadSerializeObj() As Preference
'Check if new file need created
If File.Exists("C:\Users\454\Desktop\test.xml") = False Then
SaveSerializeObj()
End If
'Deserialize text file to a new object.
Dim objStreamReader As New StreamReader("C:\Users\454\Desktop\test.xml")
Dim newObj As New Preference
Dim x As New XmlSerializer(newObj.GetType)
newObj = CType(x.Deserialize(objStreamReader), Preference)
objStreamReader.Close()
Return newObj
End Function
The best option is to create a class that would have properties for your form controls. Then you can store these properties and then access these when needed.
Also there's really no reason to be passing data back and forth, you can store this data off somewhere (database, file, mysettings etc) and then load this data up into a class. Then you can store and retrieve data from this class. Then if you need to save data back to somewhere you have a class object to use.
Here is a short example to show how you can create another form (Preferences) click save and then show those values back on the other form (calling form).
This is the main form
Public Class Form1
Public _frm2 As Form2
Private Sub btnShowPreferences_Click(sender As Object, e As EventArgs) Handles btnShowPreferences.Click
Using _frm2 As New Form2()
'if we clicked save on the form then show the values in the
'controls that we want to
If _frm2.ShowDialog() = Windows.Forms.DialogResult.OK Then
txtFirstName.Text = _frm2._Preferences.FirstName
txtLastName.Text = _frm2._Preferences.LastName
End If
End Using
End Sub
End Class
Here is an example (Preferences) class
This class would hold all your properties for the preferences. This is an example, you can change anything you need to suit your needs.
Option Strict On
Public Class Preferences
#Region "Properties"
Public Property FirstName As String
Public Property LastName As String
#End Region
Public Sub New()
End Sub
End Class
The second Form could be your (Preference) form with all the controls a user would need to interact with.
Public Class Form2
Public _Preferences As New Preferences 'create class variable you can use for later to store data
Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
'set your properties of the class from your form. this will then hold everything you can get from
'the first form...
With _Preferences
.FirstName = txtFirstName.Text
.LastName = txtLastName.Text
End With
Me.DialogResult = Windows.Forms.DialogResult.OK 'this is used to determine if user clicked a save button...
End Sub
End Class
I hope this get's you started, if you do not understand something please let me know.
To directly answer your question, the main difference in your two code samples is that the second uses ShowDialog to open the form modally, vs the first sample which lets you interact with the parent form while the second is open.
The second approach may be better from the view of user flow control. If your real question is whether to push data back to the main form or pull data from the dialog, it is probably better to pull from the dialog. This approach makes the dialog reusable from other forms.
I need to access textbox values that are in Form1 from Module1 in my VB.net program. I thought I read somewhere that you can make your controls Public and then you can access the values. I tried this but it does not work. What do I need to do?
Here is my code:
Module Module1
Dim connectionMaster = New ConnectionMaster()
Dim uname As String
Dim pw As String
Dim frmInstance As Form2
frmInstance = New Form2
uname = frmInstance.Username
pw = frmInstance.Password
Username and Password are in Form2. When I try to build this, I get the error message "Value of type 'System.Windows.Forms.TextBox' cannot be converted to 'String'"
I changed the above to:
uname = frmInstance.Username.text
pw = frmInstance.Password.text
and now it works!
One simple way to do this is to create 2 public properties in your module.
Private _name As String
Public Property UserName() As String
Get
Return _username
End Get
Private Set(ByVal value As String)
_username = value
End Set
End Property
Then in your form, upon calling your module, you just need to pass the value to the module.
I've created a request class. Here is an abbreviated version of it:
Public Class Request(Of T)
Private _Account As String
Public Property Account() As String
Get
Return _Account
End Get
Set(ByVal value As String)
_Account = value
End Set
End Property
Private _InnerRequest As T
Public Property InnerRequest() As T
Get
Return Me._InnerRequest
End Get
Set(ByVal value As T)
Me._InnerRequest = value
End Set
End Property
End Class
And then I have two other classes that I intend to use with this one - again, abbreviated
Public Class Individual
Public FirstName As String
Public LastName As String
Friend Sub New()
End Sub
End Class
And
Public Class Commercial
Public EntityName As String
Friend Sub New()
End Sub
End Class
Again, both of these are pretty abbreviated. The issue comes in when I attempt to use the properties of individual or commercial:
Dim Req As New Request(Of Individual)()
Req.InnerRequest.FirstName = "Herman" <-- Null Ref Exception
So... how do I get my inner request null ref exception kicked? I tried simply using Me._InnerRequest = New T in the New sub of Request, but no dice. Is there a way to handle this?
Req.InnerRequest must be set to an object instance of Individual first.
Req.InnerRequest = new Individual()
Req.InnerRequest.FirstName = "Herman"
Or create an instance for InnerRequest with the following modifications
Public Class Request(Of T As {New}) 'Classes of type T must have a public new constructor defined
::
Private _InnerRequest As New T() 'Creates a new class of type T when an instance is created of Request
And make the constructors of the other classes Public instead of Friend.
Than you can directly do
Dim Req As New Request(Of Individual)()
Req.InnerRequest.FirstName = "Herman"
#Barry already answered what the main problem is, but here's an alternate syntax if you prefer object initializers:
Req.InnerRequest = new Individual() With { FirstName = "Herman" }
Or, if you prefer, you could overload the constructor for your Individual class:
Dim individual As New Individual("Herman")
Req.InnerRequest = individual
With the Individual class looking like:
Public Class Individual
Public FirstName As String
Public LastName As String
Friend Sub New()
End Sub
Friend Sub New(firstName As String)
Me.FirstName = firstName
End Sub
End Class
You probably should consider restricting the T to some Entity class:
Public Class Request(Of T As Entity)
From which both Individual and Commercial will inherit:
Public Class Individual : Inherits Entity
Then maybe declare an overridable property Name of type String on this Entity class (which can be abstract/MustInherit), this should provide some flexibility. Otherwise you'd be having a hard time consuming your design pattern.
Goal: filling some TextBoxes
Problem: when the first TextBox is filled, the values of the next ones are compromised. It happens in three steps.
First step. Say I have to fill two TextBoxes. A public function does this:
Public Sub FillingTextBoxes(Name As String)
'Fetching my object from a collection
Dim newObject As MyClass = MyCollection.Item(Name)
'Filling two textboxes
With newObject
TextBox1.Text = .Property1.ToString
TextBox2.Text = .Property2.ToString
MyCollection is a public Microsoft.VisualBasic.Collection.
Second step. Filling TextBox1 triggers a TextChanged event. Another public function changes the values of the same object:
Public Sub SomeOtherFunction(Name As String)
Dim newObject As MyClass = MyCollection.Item(Name)
newObject.Property2 = "something else"
Third step, here it comes. When SomeOtherFunction is done running, back in FillingTextBoxes, the value of newObject.Property2 is now "something else", even though this happened in another function.
How could I possibly solve this?
If what you are storing in the collection is a custom class then you need to implement a clone function that allows a deep copy.
Clone funcionality allows you to take an object reference and return a new copy of that same type that is a new reference to a different object. For example if you had this:
public class MyClass
public Property1 as string
public Property2 as string
public sub new()
Property1 = string.empty
Property2 = string.empty
end sub
public function clone() as MyClass
dim returnThis as new MyClass
returnThis.Property1 = Property1
returnThis.Property2 = Property2
return returnThis
end function
end class
Then you could call for a new deep copy like this:
Public Sub SomeOtherFunction(Name As String)
Dim newObject As MyClass = MyCollection.Item(Name).clone()
newObject.Property2 = "something else"
And you would have no problems because you are using a new copy of the same object instead of the reference in the collection.