Hi Admin,
The dropdownlist of autocompletemode is suggest and dropdownlist of dropdownstyle is dropdown.
I have two dropdownlist. First is Category and second details.
First Category data are Green,Red and Orange.
Second Details data are Avocado, Green apple, Green grape, Kiwi, Pear, Honeydew Melon, Raspberry, Strawberry, cherry, Orange, Papaya, Tangerines, Pumpkin and Plum.
When I key in detail dropdownlist start from 'P' and I choose 'Plum' and Category dropdownlist auto change to Red but second dropdownlist automatically choose Strawberry.
If Category choose blank , all dropdownlist reset. If Category choose green, detail dropdownlist need to show green category code of fruit. No need to show all value.
Below my testing coding.
Imports Telerik.WinControls.UI
Public Class RadForm1
Property FolderCodeToUse As Nullable(Of Integer)
Property DocumentTypeCodeToUse As Nullable(Of Integer)
Property DocumentDescriptionToUse As String
Property BlnSuppressFolderCode As Boolean
Property BlnSuppressDocumentTypeCode As Boolean
Property font As New Font("Arial", 14)
Property ListOfDocumentTypes As List(Of DocumentTypes)
Private Sub RadForm1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
ListOfDocumentTypes = New List(Of DocumentTypes)
Dim lstfoldercode As New List(Of DocumentTypes)
Dim fold1 As New DocumentTypes
fold1.FolderCode = 1
fold1.FolderNameText = "Green"
lstfoldercode.Add(fold1)
fold1 = New DocumentTypes
fold1.FolderCode = 2
fold1.FolderNameText = "Red"
lstfoldercode.Add(fold1)
fold1 = New DocumentTypes
fold1.FolderCode = 3
fold1.FolderNameText = "Orange"
lstfoldercode.Add(fold1)
lstfoldercode.Insert(0, New DocumentTypes)
Dim doc1 As New DocumentTypes
doc1.FolderCode = 1
doc1.FolderNameText = "Green"
doc1.DocumentTypeCode = 1
doc1.DocumentTypeDescription = "Avocado"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 1
doc1.FolderNameText = "Green"
doc1.DocumentTypeCode = 2
doc1.DocumentTypeDescription = "Green apple"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 1
doc1.FolderNameText = "Green"
doc1.DocumentTypeCode = 2
doc1.DocumentTypeDescription = "Green grape"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 1
doc1.FolderNameText = "Green"
doc1.DocumentTypeCode = 3
doc1.DocumentTypeDescription = "Kiwi"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 1
doc1.FolderNameText = "Green"
doc1.DocumentTypeCode = 4
doc1.DocumentTypeDescription = "Pear"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 1
doc1.FolderNameText = "Green"
doc1.DocumentTypeCode = 5
doc1.DocumentTypeDescription = "Honeydew Melon"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 2
doc1.FolderNameText = "Red"
doc1.DocumentTypeCode = 1
doc1.DocumentTypeDescription = "Raspberry"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 2
doc1.FolderNameText = "Red"
doc1.DocumentTypeCode = 6
doc1.DocumentTypeDescription = "Strawberry"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 2
doc1.FolderNameText = "Red"
doc1.DocumentTypeCode = 7
doc1.DocumentTypeDescription = "Cherry"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 3
doc1.FolderNameText = "Orange"
doc1.DocumentTypeCode = 8
doc1.DocumentTypeDescription = "Orange"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 3
doc1.FolderNameText = "Orange"
doc1.DocumentTypeCode = 9
doc1.DocumentTypeDescription = "Papaya"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 3
doc1.FolderNameText = "Orange"
doc1.DocumentTypeCode = 10
doc1.DocumentTypeDescription = "Tangerines"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 3
doc1.FolderNameText = "Orange"
doc1.DocumentTypeCode = 11
doc1.DocumentTypeDescription = "Pumpkin"
ListOfDocumentTypes.Add(doc1)
doc1 = New DocumentTypes
doc1.FolderCode = 2
doc1.FolderNameText = "Red"
doc1.DocumentTypeCode = 12
doc1.DocumentTypeDescription = "Plum"
ListOfDocumentTypes.Add(doc1)
ListOfDocumentTypes.Insert(0, New DocumentTypes)
Me.RadDropDownList2.ValueMember = "DocumentTypeCode"
Me.RadDropDownList2.DisplayMember = "DocumentTypeDescription"
Me.BlnSuppressDocumentTypeCode = True
Me.RadDropDownList2.DataSource = Me.ListOfDocumentTypes.ToList
Me.BlnSuppressDocumentTypeCode = False
Me.RadDropDownList2.Refresh()
For Each item As RadListDataItem In RadDropDownList1.ListElement.Items
item.Font = font
Next
Me.RadDropDownList1.ValueMember = "FolderCode"
Me.RadDropDownList1.DisplayMember = "FolderNameText"
Me.BlnSuppressFolderCode = True
Me.RadDropDownList1.DataSource = lstfoldercode.ToList
Me.BlnSuppressFolderCode = False
Me.RadDropDownList1.Refresh()
For Each item As RadListDataItem In RadDropDownList1.ListElement.Items
item.Font = font
Next
End Sub
Private Sub RadDropDownList1_SelectedValueChanged(sender As Object, e As EventArgs) Handles RadDropDownList1.SelectedValueChanged
Try
If Me.BlnSuppressFolderCode Then
Exit Sub
End If
Dim CategoryCode As Integer = CInt(RadDropDownList1.SelectedValue)
RadDropDownList1.DataSource = Nothing
RadDropDownList1.Refresh()
LoadDetailBasedOnCategory(CategoryCode)
Catch ex As Exception
End Try
End Sub
Private Sub RadDropDownList2_SelectedValueChanged(sender As Object, e As EventArgs) Handles RadDropDownList2.SelectedValueChanged
Try
If Me.BlnSuppressDocumentTypeCode Then
Exit Sub
End If
Dim detailstypeCode As Integer = CInt(RadDropDownList2.SelectedValue)
If detailstypeCode = 0 Then
Exit Sub
End If
Dim categoryCodeSelected As Integer = CInt(RadDropDownList1.SelectedValue)
If categoryCodeSelected = 0 Then
'STEP 5. Find the FolderCode based on the DocumentTypeCode selected
For Each detailTypes1 As DocumentTypes In Me.ListOfDocumentTypes
If detailTypes1.DocumentTypeCode = detailstypeCode Then
categoryCodeSelected = detailTypes1.FolderCode
Exit For
End If
Next
Me.DocumentTypeCodeToUse = detailstypeCode
Me.BlnSuppressFolderCode = True
RadDropDownList1.SelectedValue = categoryCodeSelected
Me.BlnSuppressFolderCode = False
LoadDetailBasedOnCategory(categoryCodeSelected)
Me.BlnSuppressDocumentTypeCode = True
RadDropDownList2.SelectedValue = Me.DocumentTypeCodeToUse.Value
Me.BlnSuppressDocumentTypeCode = False
Me.DocumentTypeCodeToUse = New Nullable(Of Integer)
End If
Catch ex As Exception
End Try
End Sub
Private Sub LoadDetailBasedOnCategory(folderCodeSelected As Integer)
Try
'STEP 1. Get the list of DocumentTypeCode based on the FolderCode
Dim listOfDocumentTypesToShow As New List(Of DocumentTypes)
If folderCodeSelected = 0 Then
For Each documentTypes1 As DocumentTypes In Me.ListOfDocumentTypes.ToList
listOfDocumentTypesToShow.Add(documentTypes1)
Next
ElseIf folderCodeSelected > 0 Then
For Each documentTypes1 As DocumentTypes In Me.ListOfDocumentTypes.ToList
If documentTypes1.FolderCode = folderCodeSelected Then
listOfDocumentTypesToShow.Add(documentTypes1)
End If
Next
End If
'STEP 2. Sort
If listOfDocumentTypesToShow.Count >= 1 Then
listOfDocumentTypesToShow.Sort(Function(x, y)
Dim compare As Integer = 0
If Not String.IsNullOrEmpty(x.DocumentTypeDescription) AndAlso Not String.IsNullOrEmpty(y.DocumentTypeDescription) Then
compare = x.DocumentTypeDescription.CompareTo(y.DocumentTypeDescription)
End If
Return compare
End Function)
'STEP 3. Insert blank first row
listOfDocumentTypesToShow.Insert(0, New DocumentTypes)
End If
'STEP 4. Load data into dropdownlist (suppress any event handler)
RadDropDownList2.ValueMember = "DocumentTypeCode"
RadDropDownList2.DisplayMember = "DocumentTypeDescription"
Me.BlnSuppressDocumentTypeCode = True
RadDropDownList2.DataSource = listOfDocumentTypesToShow.ToList
Me.BlnSuppressDocumentTypeCode = False
RadDropDownList2.Refresh()
For Each ListItem In RadDropDownList2.Items
ListItem.Font = font
Next
Catch ex As Exception
End Try
End Sub
End Class
Public Class DocumentTypes
Property DocumentTypeCode As Integer
Property FolderCode As Integer
Property FolderNameText As String
Property DocumentTypeDescription As String
End Class
Thanks
Moe
1 Answer, 1 is accepted
The provided sample project is greatly appreciated.
After a deep look into your code, I have found out that you are using an approach with two-way cascading combo boxes in combination with auto complete functionality. In this case when you type "Plu" in the Detail RadDropDownList the auto complete popup with suggestions is opened. Then, you select the first item in the pop-up("Plum"). This triggers the SelectedValueChanged event in RadDropDownList, where your logic is executed. You assign a value to the Category RadDropDownList and then, based on this value, you repopulate with items the Detail RadDropDownList. This all happens while the auto complete pop-up is trying to set SelectedIndex to the Detail RadDropDownList. When the pop-up was opened the selected index of "Plum" is 14, but after the rebind the total amount of items in Detail RadDropDownList is reduced to 5. Now, the pop-up tries to set SelectedIndex=14, but this is not valid anymore and that is why the last item is selected(the "Strawberry" item).
I have invested some time and effort to find a solution for this case and most of the time this two-way cascaded combos were into a dead lock situation. Fortunately, I have managed to find a working solution for your case, when I moved your rebinding logic when Detail RadDropDownList loses the input focus(on the Leave event). Refer to the attached project
An alternative solution is to use a one-way combo-box direction, as this will reduce the complexity of the code. For example: a car type drop down and a car model drop down - you cannot enter the model until the make field is empty.
I hope this helps. Should you have any other questions do not hesitate to ask.
Regards,
Todor Vyagov
Progress Telerik