Reversing the order of an Array or String

Question

User-1031976281 posted

Im looking to dynamically populate a Placeholder with data sent from a textbox on the same page, but in reverse order i.e. the latest post goes to the top ratehr than the bottom - kidda like Twitter or Facebook.

The code I have so far is below but I keep geeting an error stating that "BC30311: Value of type 'System.Collections.ArrayList' cannot be converted to 'System.Array'."

Please help....

 

    Protected Sub AddNewWordButton_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles AddNewWordButton.Click

        Dim DictionaryArrayList As ArrayList = New ArrayList()
        If (Me.ViewState("words") IsNot Nothing) Then
            DictionaryArrayList = ViewState("words")
        End If

        Dim newword As String = AddNewWordTextBox.Text
        DictionaryArrayList.Add(newword)
        ViewState("words") = DictionaryArrayList
        DynamicDisplay()

    End Sub

    Public Sub DynamicDisplay()

        Dim DictionaryArrayList As ArrayList = New ArrayList()
        DictionaryArrayList = ViewState("words")

        For x = 0 To DictionaryArrayList.Count - 1

            Dim holder As New PlaceHolder
            holder.Controls.Add(New LiteralControl("(" & x + 1 & ") "))
            holder.Controls.Add(New LiteralControl(DictionaryArrayList(x).ToString()))
            Array.Reverse(DictionaryArrayList)
            holder.Controls.Add(New LiteralControl("   "))

            Dim theDeleteButton As Button = New Button()
            theDeleteButton.ID = "deletebutton" & x.ToString()
            theDeleteButton.Text = "X"
            theDeleteButton.Attributes.Add("OnClick", "DeleteButtonClick();")
            holder.Controls.Add(theDeleteButton)
            holder.Controls.Add(New LiteralControl("<br />"))
            dictionaryplaceholder.Controls.Add(holder)
            AddNewWordTextBox.Text = String.Empty
        Next

    End Sub

 

Answer 1

User-1618234021 posted

Modify DynamicDisplay sub as following:

Public Sub DynamicDisplay()

        Dim DictionaryArrayList As ArrayList = New ArrayList()
        DictionaryArrayList = ViewState("words")

        For x = 0 To DictionaryArrayList.Count - 1

            Dim holder As New PlaceHolder
            holder.Controls.Add(New LiteralControl("(" & x + 1 & ") "))
            holder.Controls.Add(New LiteralControl(DictionaryArrayList(x).ToString()))
            'Use ToArray() to convert ArrayList to Array
             '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
            Array.Reverse(DictionaryArrayList.ToArray())
            holder.Controls.Add(New LiteralControl("   "))

            Dim theDeleteButton As Button = New Button()
            theDeleteButton.ID = "deletebutton" & x.ToString()
            theDeleteButton.Text = "X"
            theDeleteButton.Attributes.Add("OnClick", "DeleteButtonClick();")
            holder.Controls.Add(theDeleteButton)
            holder.Controls.Add(New LiteralControl("<br />"))
            dictionaryplaceholder.Controls.Add(holder)
            AddNewWordTextBox.Text = String.Empty
        Next

    End Sub

Answer 2

User-1031976281 posted

Hi,

Thanks for this, but it still doesn't work.

 

Although the code will now compile, it doesn't reverse the order of the array..

Answer 3

User-1618234021 posted

Use the following code to reverse the arraylist

ArrayList al = new ArrayList();
            al.Add("Adeel");
            al.Add("Ehsan");
            object[] ob = al.ToArray();
            Array.Reverse(ob);
            foreach (object o in ob)
            {
                Response.Write(o.ToString() + "<br>");
            }

Answer 4

User-1031976281 posted

Hi, Thanks for this it works a treat once I converted it to VB.

 

However, I can't see how I can control the positioning, the text szie, font, etc

 

Please Help! :) 

Answer 5

User-1509636757 posted

However, I can't see how I can control the positioning, the text szie, font, etc

i understand that you have data ready and you need to control on positioning, text size and other design things..

what you can do is have an html format (possibly in a .htm file) with required tokens in it (like %firstName%, %lastName%) for you data .. read that file in above for loop, replace the data with tokens and create a string like that.. finally write that string to response object..

hope it helps.

Answer 6

User-1802908944 posted

use it in vb.net

Function Reverse(ByVal value As String) As String
        ' Convert to char array.
        Dim arr() As Char = value.ToCharArray()
        ' Use Array.Reverse function.
        Array.Reverse(arr)
        ' Construct new string.
        Return New String(arr)

    End Function

happy coding

Answer 7

User-1031976281 posted

Thanks for your help you guys - I eventually stumbled upon the following code which has reversed the output for me....

 

  For x As Integer = DictionaryArrayList.Count - 1 To 0 Step -1

 

All I needed to do was replace the following line with the one above

For x = 0 To DictionaryArrayList.Count - 1