String manipulation in VB.NET

Question

User-809753952 posted

Let us say I have a string like this:

 Task_Name asc ,task_no asc ,Stage_Name asc ,Priority_name asc , 

Suppose if I want to add text PIC asc, it is allwoed.  So the string becomes   

Task_Name asc ,task_no asc ,Stage_Name asc ,Priority_name asc , PIC asc 

If I want to add task_no asc, it should not happen as it is already found in the string.

But if I want to add task_no desc, then I should remove task_no asc and then add  task_no desc to string. 

So my string becomes:  

Task_Name asc ,task_no desc ,Stage_Name asc ,Priority_name asc , PIC asc 

Please help me with some algorithm or sample code.

Answer 1

User-893317190 posted

Hi mnmhemaj,

You could try the code below.

 Private Function getString(ByVal origin As String, ByVal add As String) As String
        'check whether add is end with asc or desc if not it is not valid , return origin
        If Not add.TrimEnd(" ").EndsWith(" asc") And Not add.TrimEnd(" ").EndsWith(" desc") Then

            Return origin
        End If

        ' split the string into string array , for example Task_Name asc ,task_no asc  
        ' will becom ("Task_Name asc ","task_no asc")
        Dim strs As String() = origin.Split(New Char() {","c}, StringSplitOptions.RemoveEmptyEntries)
        ' check whether the array contains the string to add
        If Not origin.Contains(add.Trim(" ")) Then

            For index = 0 To strs.Length - 1
                'loop through the splited string to see whether one of the elements has the same prefix
                'if so replace it with the variable add, if not return origin + " ,"+add
                If add.Substring(0, add.TrimEnd(" ").LastIndexOf(" ")) = strs(index).Substring(0, strs(index).TrimEnd().LastIndexOf(" ")) Then
                    strs(index) = add
                    Return String.Join(",", strs)
                End If


            Next
            Return origin + " ," + add
        End If
        Return origin
    End Function

My test.

 Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim str As String = "Task_Name asc ,task_no asc ,Stage_Name asc ,Priority_name asc"

        Response.Write("<span style='color:blue'>add  pic asc: </span>" + getString(str, "pic asc") + "<br/>")
        Response.Write("<span style='color:blue'>add Task_Name asc:</span>" + getString(str, "Task_Name asc") + "<br/>")
        Response.Write("<span style='color:blue'>add Task_Name desc:</span>" + getString(str, "Task_Name desc"))

    End Sub

The result.

Best regards,

Ackerly Xu

Answer 2

User-809753952 posted

I solved it in another way:

Dim sortdir As String = ""
If GridView1.SortDirection.ToString = "Ascending" Then
sortdir = " asc "
ElseIf GridView1.SortDirection.ToString = "Descending" Then
sortdir = " desc "
End If
If lblSort.Text <> "" Then
Dim mystr As String = lblSort.Text
Dim cut_at As String = GridView1.SortExpression

Dim x As Integer = InStr(mystr, cut_at)

If x = 0 Then
lblSort.Text = lblSort.Text & GridView1.SortExpression & " " & sortdir
Else

Dim tobereplaced As String = mystr.Substring(x - 1, Len(cut_at) + 6)

lblSort.Text = mystr.Replace(tobereplaced, "")
lblSort.Text = lblSort.Text & GridView1.SortExpression & " " & sortdir
End If

Else
lblSort.Text = lblSort.Text & GridView1.SortExpression & " " & sortdir
End If