how to add value to combobox item - vb.net

How can I add data value of each item to combobox in Visual Basic 2010?
Like html drop-down box.
Or is there anyway to add values to each item ?
I am adding item from MySQL database like this:
Command = New MySqlCommand("SELECT * FROM `maillist` WHERE l_id = '" & id & "'", connection)
Command.CommandTimeout = 30
Reader = Command.ExecuteReader()
If Reader.HasRows = True Then
While Reader.Read()
ComboBox1.Items.Add(Reader("name"))
End While
End If
I need to add Reader("ID") as value of each item...

Although this question is 5 years old I have come across a nice solution.
Use the 'DictionaryEntry' object to pair keys and values.
Set the 'DisplayMember' and 'ValueMember' properties to:
Me.myComboBox.DisplayMember = "Key"
Me.myComboBox.ValueMember = "Value"
To add items to the ComboBox:
Me.myComboBox.Items.Add(New DictionaryEntry("Text to be displayed", 1))
To retreive items like this:
MsgBox(Me.myComboBox.SelectedItem.Key & " " & Me.myComboBox.SelectedItem.Value)

I am assuming that you are wanting to add items to a ComboBox on an Windows form. Although Klaus is on the right track I believe that the ListItem class is a member of the System.Web.UI.WebControls namespace. So you shouldn't be using it in a Windows forms solution. You can, however, create your own class that you can use in its place.
Create a simple class called MyListItem (or whatever name you choose) like this:
Public Class MyListItem
Private mText As String
Private mValue As String
Public Sub New(ByVal pText As String, ByVal pValue As String)
mText = pText
mValue = pValue
End Sub
Public ReadOnly Property Text() As String
Get
Return mText
End Get
End Property
Public ReadOnly Property Value() As String
Get
Return mValue
End Get
End Property
Public Overrides Function ToString() As String
Return mText
End Function
End Class
Now when you want to add the items to your ComboBox you can do it like this:
myComboBox.Items.Add(New MyListItem("Text to be displayed", "value of the item"))
Now when you want to retrieve the value of the selected item from your ComboBox you can do it like this:
Dim oItem As MyListItem = CType(myComboBox.SelectedItem, MyListItem)
MessageBox.Show("The Value of the Item selected is: " & oItem.Value)
One of the keys here is overriding the ToString method in the class. This is where the ComboBox gets the text that is displayed.
Matt made an excellent point, in his comment below, about using Generics to make this even more flexible. So I wondered what that would look like.
Here's the new and improved GenericListItem class:
Public Class GenericListItem(Of T)
Private mText As String
Private mValue As T
Public Sub New(ByVal pText As String, ByVal pValue As T)
mText = pText
mValue = pValue
End Sub
Public ReadOnly Property Text() As String
Get
Return mText
End Get
End Property
Public ReadOnly Property Value() As T
Get
Return mValue
End Get
End Property
Public Overrides Function ToString() As String
Return mText
End Function
End Class
And here is how you would now add Generic items to your ComboBox. In this case an Integer:
Me.myComboBox.Items.Add(New GenericListItem(Of Integer)("Text to be displayed", 1))
And now the retrieval of the item:
Dim oItem As GenericListItem(Of Integer) = CType(Me.myComboBox.SelectedItem, GenericListItem(Of Integer))
MessageBox.Show("The value of the Item selected is: " & oItem.Value.ToString())
Keep in mind that the type Integer can be any type of object or value type. If you want it to be an object from one of your own custom classes that's fine. Basically anything goes with this approach.

If you want to use SelectedValue then your combobox must be databound.
To set up the combobox:
ComboBox1.DataSource = GetMailItems()
ComboBox1.DisplayMember = "Name"
ComboBox1.ValueMember = "ID"
To get the data:
Function GetMailItems() As List(Of MailItem)
Dim mailItems = New List(Of MailItem)
Command = New MySqlCommand("SELECT * FROM `maillist` WHERE l_id = '" & id & "'", connection)
Command.CommandTimeout = 30
Reader = Command.ExecuteReader()
If Reader.HasRows = True Then
While Reader.Read()
mailItems.Add(New MailItem(Reader("ID"), Reader("name")))
End While
End If
Return mailItems
End Function
Public Class MailItem
Public Sub New(ByVal id As Integer, ByVal name As String)
mID = id
mName = name
End Sub
Private mID As Integer
Public Property ID() As Integer
Get
Return mID
End Get
Set(ByVal value As Integer)
mID = value
End Set
End Property
Private mName As String
Public Property Name() As String
Get
Return mName
End Get
Set(ByVal value As String)
mName = value
End Set
End Property
End Class

Instead of adding Reader("Name") you add a new ListItem. ListItem has a Text and a Value property that you can set.

Yeah, for most cases, you don't need to create a class with getters and setters. Just create a new Dictionary and bind it to the data source. Here's an example in VB using a for loop to set the DisplayMember and ValueMember of a combo box from a list:
Dim comboSource As New Dictionary(Of String, String)()
cboMenu.Items.Clear()
For I = 0 To SomeList.GetUpperBound(0)
comboSource.Add(SomeList(I).Prop1, SomeList(I).Prop2)
Next I
cboMenu.DataSource = New BindingSource(comboSource, Nothing)
cboMenu.DisplayMember = "Value"
cboMenu.ValueMember = "Key"
Then you can set up a data grid view's rows according to the value or whatever you need by calling a method on click:
Private Sub cboMenu_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cboMenu.SelectionChangeCommitted
SetListGrid(cboManufMenu.SelectedValue)
End Sub

Now you can use insert method instead add
' Visual Basic
CheckedListBox1.Items.Insert(0, "Copenhagen")

Related

Sort an arraylist of objects by one of the properties?

Hi I have an object called item here is the code for it:
Public Class item
Private itemValue As String
Private urlfoundValue As String
Private typeValue As String
Private scorevalue As String
Public Sub New()
' Leave fields empty.
End Sub
Public Sub New(ByVal item As String, ByVal urlfound As String, ByVal type As String, ByVal score As String)
itemValue = item
urlfoundValue = urlfound
typeValue = type
scorevalue = score
End Sub
Public Property item() As String
Get
Return itemValue
End Get
Set(ByVal value As String)
itemValue = value
End Set
End Property
Public Property urlfound() As String
Get
Return urlfoundValue
End Get
Set(ByVal value As String)
urlfoundValue = value
End Set
End Property
Public Property type() As String
Get
Return typeValue
End Get
Set(ByVal value As String)
typeValue = value
End Set
End Property
Public Property score() As String
Get
Return scorevalue
End Get
Set(ByVal value As String)
scorevalue = value
End Set
End Property
I have an ArrayList of these items that I would like to sort in highest to lowest order by the Score property (is string but can be converted to int32).
The items are all store in this arraylist:
Public fullitem As New System.Collections.ArrayList()
Any suggestions on how to get the items in order by the score? Can be done in c# too.
A direct answer to your question is to use LINQ like this:
Dim orderdList = fullitem.Cast(Of item)() _
.OrderBy(Function(i As item) Convert.ToInt32(i.score))
fullitem = New System.Collections.ArrayList()
For Each item In orderdList
fullitem.Add(item)
Next
This uses Cast to obtain a generic IEnumerable<item> from the ArrayList which then enables you to use LINQ functions like OrderBy.
However, please note that ArrayList is now obsolete, and you should consider using List<Item> instead. If you do that then you can do something as simple as this:
Assuming you have the list defined like this:
Dim list = new List(Of item)()
You can sort it like this:
list = list.Cast(Of item)() _
.OrderBy(Function(i As item) Convert.ToInt32(i.score)) _
.ToList()

Extracting property values from a dictionary

I am attempting to write a subroutine that will deserialize a dictionary from a .ser file (this bit works fine) and then repopulate several lists from this dictionary (this is the bit I cannot do).
The dictionary contains objects (I think) of a custom class I wrote called "Photo Job" which has properties such as ETA, notes, medium etc. (Declared as such)
Dim photoJobs As New Dictionary(Of String, PhotoJob)
In short, I want to be able to extract every entry of each specific property into an separate arrays (one for each property) and I can go from there.
Any help would be appreciated, I may be going about this completely the wrong way, I'm new to VB. The relevant code is below:
Photo Job Class:
<Serializable()> _Public Class PhotoJob
Private intStage As Integer 'Declare all local private variables
Private ID As String
Private timeLeft As Integer
Private material As String '
Private note As String
Private path As String
Private finished As Boolean = False
'Declare and define properties and methods of the class
Public Property productionStage() As Integer
Get
Return intStage
End Get
Set(ByVal Value As Integer)
intStage = Value
End Set
End Property
Public Property photoID() As String
Get
Return ID
End Get
Set(ByVal Value As String)
ID = Value
End Set
End Property
Public Property ETA() As Integer
Get
Return timeLeft
End Get
Set(ByVal Value As Integer)
timeLeft = Value
End Set
End Property
Public Property medium() As String
Get
Return material
End Get
Set(ByVal Value As String)
material = Value
End Set
End Property
Public Property notes() As String
Get
Return note
End Get
Set(ByVal Value As String)
note = Value
End Set
End Property
Public Property imagePath() As String
Get
Return path
End Get
Set(ByVal Value As String)
path = Value
End Set
End Property
Public Property complete() As Boolean
Get
Return finished
End Get
Set(value As Boolean)
finished = value
End Set
End Property
Public Sub nextStage()
If intStage < 4 Then
intStage += 1
ElseIf intStage = 4 Then
intStage += 1
finished = True
End If
End Sub
End Class
Subroutines involved in de/serialisation:
Private Sub BackupAllToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles BackupAllToolStripMenuItem.Click
Dim formatter As New BinaryFormatter
Dim backupFile As New FileStream(Strings.Replace(Strings.Replace(Now, ":", "_"), "/", ".") & ".ser", FileMode.Create, FileAccess.Write, FileShare.None)
formatter.Serialize(backupFile, photoJobs)
backupFile.Close()
MsgBox("Collection saved to file")
End Sub
Private Sub RestoreFromFileToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles RestoreFromFileToolStripMenuItem.Click
With OpenFileDialog 'Executes the following sets/gets/methods of the OpenFileDialog
.FileName = ""
.Title = "Open Image File"
.InitialDirectory = "c:\"
.Filter = "Serial Files(*.ser)|*ser"
.ShowDialog()
End With
Dim backupPathStr As String = OpenFileDialog.FileName
Dim deSerializer As New BinaryFormatter
Dim backupFile As New FileStream(backupPathStr, FileMode.Open)
photoJobs = deSerializer.Deserialize(backupFile)
backupFile.Close()
End Sub
From what I can see using the autos menu, the saving/restoring of the dictionary works just fine.
First, if you are using VS2010+, you can greatly reduce boilerplate code using autoimplemented properties:
<Serializable()>
Public Class PhotoJob
Public Property productionStage() As Integer
Public Property photoID() As String
Public Property ETA() As Integer
etc
End Class
That is all that is needed, all the boilerplate code is handled for you. Second, with this line:
photoJobs = deSerializer.Deserialize(backupFile)
Your deserialized photojobs will be a generic Object, not a Dictionary. You should turn on Option Strict so VS will enforce these kinds of errors. This is how to deserialize to Type:
Using fs As New FileStream(myFileName, FileMode.Open)
Dim bf As New BinaryFormatter
PhotoJobs= CType(bf.Deserialize(fs), Dictionary(Of String, PhotoJob))
End Using
Using closes and disposes of the stream, CType converts the Object returned by BF to an actual dictionary
To work with the Dictionary (this has nothing to do with Serialization) you need to iterate the collection to get at the data:
For Each kvp As KeyValuePair(Of String, PhotoJob) In PhotoJobs
listbox1.items.Add(kvp.value.productionStage)
listbox2.items.Add(kvp.value.ETA)
etc
Next
The collection is a made of (String, PhotoJob) pairs as in your declaration, and when you add them to the collection. They comeback the same way. kvp.Key will be the string key used to identify this job in the Dictionary, kvp.Value will be a reference to a PhotoJobs object.
As long as VS/VB knows it is a Dictionary(of String, PhotoJob), kvp.Value will act like an instance of PhotoJob (which it is).

how to pick value and name for item in listbox in vb.net

i want to pick payrollcode when listbox is selected though list should appear as payrollname.Once I have the paycode i can then use it in another query.I have a php background so this is alittle tricky for me.
Dim cmd As New SqlCommand("select tblPayrollCode.payrollcode_name ,tblPayrollCode.payrollcode_code from tblPayrollCode where tblPayrollCode.systemcode_id=0 and tblPayrollCode.deduction= 'false'", Getconnect)
Dim dr As SqlDataReader
Getconnect()
dr = cmd.ExecuteReader
While dr.Read
lsttrans.Items.Add(dr.Item("payrollcode_name"), payrollcode_code)
End While
dr.Close()
Create a class to create objects that keep each display item/data pair. The class needs to specify an overriden ToString method. This method overrides the ToString method of the base class (Object) to ensure that your display item and not the class name is displayed in the list box.
Public Class CListItem
Private m_sItemData As String
Private m_sItemDisplay As String
Public Sub New(ByVal sValue As String, ByVal sData As String)
m_sItemData = sData
m_sItemDisplay = sValue
End Sub
Public Overrides Function ToString() As String
Return m_sItemDisplay
End Function
Public Property ItemData() As String
Get
Return m_sItemData
End Get
Set(ByVal Value As String)
m_sItemData = Value
End Set
End Property
Public Property ItemDisplay() As String
Get
Return m_sItemDisplay
End Get
Set(ByVal Value As String)
m_sItemDisplay = Value
End Set
End Property
End Class
Execute the loop like this. This adds a CListItem object to the list box's items collection and displays the first parameter that is passed to the constructor.
While dr.Read
lsttrans.Items.Add(New CListItem(dr.Item("payrollcode_name").ToString, dr.Item("payrollcode_code").ToString))
End While
You can then retrieve the payrollcode_name and payrollcode_code by adding this code and double clicking on the list box:
Private Sub lsttrans_DoubleClick(sender As Object, e As EventArgs) Handles lsttrans.DoubleClick
Dim sSelectedDisplay As String = DirectCast(lsttrans.SelectedItem, CListItem).ItemDisplay
Dim sSelectedData As String = DirectCast(lsttrans.SelectedItem, CListItem).ItemData()
MessageBox.Show("The selected payrollcode_name is " & sSelectedDisplay & " and the selected payrollcode_code is " & sSelectedData)
End Sub
Adding onto #Guru Josh's answer
While dr.Read
lsttrans.Items.Add(New CListItem(dr.Item("payrollcode_name"), dr.Item("payrollcode_code")))
End While
I changed the last bit to the above works fine now.
string col1Value = dr["ColumnOneName"].ToString()

How to assign class property as display data member in datagridview

I am trying to display my data in datagridview. I created a class with different property and used its list as the datasource. it worked fine. but I got confused how to do that in case we have nested class.
My Classes are as follows:
class Category
property UIN as integer
property Name as string
end class
class item
property uin as integer
property name as string
property mycategory as category
end class
my data list as follows:
dim myDataList as list(of Item) = new List(of Item)
myDataList.Add(new Item(1,"item1",new category(1,"cat1")))
myDataList.Add(new Item(2,"item2",new category(1,"cat1")))
myDataList.Add(new Item(3,"item3",new category(1,"cat1")))
myDataList.Add(new Item(4,"item4",new category(2,"cat2")))
myDataList.Add(new Item(5,"item5",new category(2,"cat2")))
myDataList.Add(new Item(6,"item6",new category(2,"cat2")))
Now I binded the datagridview control like:
DGVMain.AutoGenerateColumns = False
DGVMain.ColumnCount = 3
DGVMain.Columns(0).DataPropertyName = "UIN"
DGVMain.Columns(0).HeaderText = "ID"
DGVMain.Columns(1).DataPropertyName = "Name"
DGVMain.Columns(1).HeaderText = "Name"
DGVMain.Columns(2).DataPropertyName = "" **'here i want my category name**
DGVMain.Columns(2).HeaderText = "category"
DGVMain.datasource = myDataList
DGVMain.refresh()
I have tried using mycategory.name but it didn't worked. What can be done to get expected result? Is there any better idea other than this to accomplish the same task?
Edited My question as per comment:
I have checked the link given by u. It was nice n very usefull. Since the code was in c# i tried to convert it in vb. Everything went good but failed at a point of case sensitive and next one is that i had my nested class name itemcategory and my property name was category. there it arouse the problem. it didn't searched for category but it searched for itemcategory. so confused on it. My Code as follows:
Private Sub DGVMain_CellFormatting(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) Handles DGVMain.CellFormatting
Dim DGVMain As DataGridView = CType(sender, DataGridView)
e.Value = EvaluateValue(DGVMain.Rows(e.RowIndex).DataBoundItem, DGVMain.Columns(e.ColumnIndex).DataPropertyName)
End Sub
Private Function EvaluateValue(ByRef myObj As Object, ByRef myProp As String) As String
Dim Ret As String = ""
Dim Props As System.Reflection.PropertyInfo()
Dim PropA As System.Reflection.PropertyInfo
Dim ObjA As Object
If myProp.Contains(".") Then
myProp = myProp.Substring(0, myProp.IndexOf("."))
Props = myObj.GetType().GetProperties()
For Each PropA In Props
ObjA = PropA.GetValue(myObj, New Object() {})
If ObjA.GetType().Name = myProp Then
Ret = EvaluateValue(ObjA, myProp.Substring(myProp.IndexOf(".") + 1))
Exit For
End If
Next
Else
PropA = myObj.GetType().GetProperty(myProp)
Ret = PropA.GetValue(myObj, New Object() {}).ToString()
End If
Return Ret
End Function
I'd just add a property to item called CategoryName that returns Category.Name and use that.
The Category is part of the Item, but that doesn't mean that you always have to give access to the whole Category to outside classes, just give access to the bits that they need access to at that time as to maximize encapsulation and minimize interdependencies.
Edit: In response to your comment
If you don't want to create the properties as mentioned in my answer above I don't think there is any real solution but you can use the 'CellFormatting' event to sort of get it to work where you set the DataPropertyName to a special identifier and then in the CellFormatting event handler you look up the real value to display. You can find an example of that here, look for tkrasinger's post (or AlexHinton's if you want to use reflection).
Public Class Category
Dim uni As Integer
Dim name As String
Public Sub New(ByVal i As Integer, ByVal n As String)
Me.UIN = i
Me.name = n
End Sub
Public Sub New()
End Sub
Property UIN() As Integer
Get
Return uni
End Get
Set(ByVal value As Integer)
uni = value
End Set
End Property
Property Names() As String
Get
Return Me.name
End Get
Set(ByVal value As String)
Me.name = value
End Set
End Property
**Public Overrides Function ToString() As String
Return name.ToString()
End Function**
End Class
Public Class item
Dim uni As Integer
Dim name As String
Dim category As New Category()
Property UIN() As Integer
Get
Return uni
End Get
Set(ByVal value As Integer)
uni = value
End Set
End Property
Property Names() As String
Get
Return Me.name
End Get
Set(ByVal value As String)
Me.name = value
End Set
End Property
Property mycategory() As Category
Get
Return Me.category
End Get
Set(ByVal value As Category)
Me.category = value
End Set
End Property
Public Sub New(ByVal i As Integer, ByVal nm As String, ByVal ct As Category)
Me.UIN = i
Me.Names = nm
Me.mycategory = ct
End Sub
End Class
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim myDataList As List(Of item) = New List(Of item)
myDataList.Add(New item(1, "item1", New Category(1, "cat1")))
myDataList.Add(New item(2, "item2", New Category(1, "cat1")))
myDataList.Add(New item(3, "item3", New Category(1, "cat1")))
myDataList.Add(New item(4, "item4", New Category(2, "cat2")))
myDataList.Add(New item(5, "item5", New Category(2, "cat2")))
myDataList.Add(New item(6, "item6", New Category(2, "cat2")))
DGVMain.AutoGenerateColumns = False
DGVMain.ColumnCount = 3
DGVMain.Columns(0).DataPropertyName = "UIN"
DGVMain.Columns(0).HeaderText = "ID"
DGVMain.Columns(1).DataPropertyName = "Names"
DGVMain.Columns(1).HeaderText = "Name"
**DGVMain.Columns(2).DataPropertyName = "mycategory"**
DGVMain.Columns(2).HeaderText = "Category"
DGVMain.datasource = myDataList
DGVMain.refresh()
End Sub

Pass string to Dialog in VB.net

I have a form and from this I call
dialogPrintDiet.ShowDialog()
which launchs my dialog. I need to pass a string value and need the easiest way to do this in VB.NET .
Try properties, for example setting some text boxes in your dialog:
Property FirstName() As String
Get
Return txtFirstName.Text
End Get
Set(ByVal Value As String)
txtFirstName.Text = Value
End Set
End Property
Property LastName() As String
Get
Return txtLastName.Text
End Get
Set(ByVal Value As String)
txtLastName.Text = Value
End Set
End Property
You can either add a property to the form or you can add a parameter to your form's constructor.
An example of the first method would look like (where Message is the name of the property)
frm.Message = "Some text"
An example of the second method would look like
Dim frm As New SampleForm ( "Some text" )
Your form code would be something like
Public Class SampleForm
Private someMessage As String
Public Sub New(ByVal msg As String)
InitializeComponent()
If Not (String.IsNullOrEmpty(msg)) Then
someMessage = msg
End If
End Sub
Property Message() As String
Get
Return someMessage
End Get
Set(ByVal Value As String)
someMessage = Value
End Set
End Property
End Class