Filter Data in the DataGrid system in 3 layers

[tsanalista]

Staff good day.
I have a problem when that will filter the data in my datagrid.
I am using a system with 3 Layers (BLL, DAL, WIN). Whenever I type something in the textbox generates this error message
/ / Error
* Unable to cast object of type 'System.Collections.Generic.List `1 [BLL.BLL.Students.BLLStudents ]' to type 'System.Data.DataView'.

Imports System
Imports System.Data
Imports System.Text
Imports System.Text.RegularExpressions
Imports BLL.BLL.Course
Imports BLL.BLL.Students
 
Public Class Form1
#Region "Private Varibales"
    Private _criar As Boolean = False
    Private _editar As Boolean = False
    Private _carregar As Boolean = True
    Private _objc As BLLCourse = Nothing
    Private _objs As BLLStudents = Nothing
    Private _dset As DataSet = Nothing
    Private _dlinha As DataRow = Nothing
    Private _retvalor As Boolean = False
    Private _cursoid As Integer = 0
 
 
 
#End Region
 
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Try
            _objs = New BLLStudents()
 
            _objs.AllStudents()
            DataGridView1.DataSource = _objs.ListaEstudantes
 
        Catch ex As Exception
            MessageBox.Show(ex.Message, Me.Text, MessageBoxButtons.OK, MessageBoxIcon.Error)
            Me.Close()
        Finally
            _objs = Nothing
        End Try
 
    End Sub
 
 
//Textbox
 
Private Sub txtsearch_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtsearch.TextChanged
 
        Try
 
            Dim txtstring As String = Me.txtsearch.Text
 
            Dim dv As DataView = Me.DataGridView1.DataSource
 
            dv.RowFilter = "StudentsName LIKE '%" + txtstring + "%'"
 
            Me.DataGridView1.DataSource = dv
 
        Catch ex As Exception
            Throw ex
        End Try
 
    End Sub
 
 
 
 
 

Here BLL Students

 
 
 
Imports System
Imports System.Data
 
Imports DAL.DAL.Students
 
Namespace BLL.Students
    Public Class BLLStudents
 
 
#Region "Variables"
 
        Private _obj As DALStudents = Nothing
        Private _retvalor As Boolean = False
        Private _dset As DataSet = Nothing
        Private _dlinha As DataRow = Nothing
        Private _idvalor As Object = Nothing
 
        Private _StudentsID As Integer
        Private _courseid As Integer
        Private _namestudents As String
        Private _addressstudents As String
        Private _phonestudents As String
        Private _agestudents As Integer
        Private _paidstudents As Boolean
        Private _liststudents As List(Of BLLStudents)
 
#End Region
 
 
     Public Sub AllStudents()
 
            _dset = Nothing
            Try
                _obj = New DALStudents()
                _dset = _obj.AllStudents()
 
                Dim objs As BLLStudents = Nothing
                _liststudents = New List(Of BLLStudents)
 
                For index As Integer = 0 To _dset.Tables(0).Rows.Count - 1
                    objs = New BLLStudents
                    objs.StudentsID = _dset.Tables(0).Rows(index)(0).ToString()
                    objs.CursoID = _dset.Tables(0).Rows(index)(1).ToString()
                    objs.EstudanteNome = _dset.Tables(0).Rows(index)(2).ToString()
                    objs.EstudanteEndereco = _dset.Tables(0).Rows(index)(3).ToString()
                    objs.Telefone = _dset.Tables(0).Rows(index)(4).ToString()
                    _liststudents.Add(objs)
                    objs = Nothing
                Next
 
            Catch ex As Exception
                Throw ex
            Finally
                _obj = Nothing
            End Try
 
        End Sub
 
 

I'll leave here a sample of Crud if you want to test:

https://skydrive.live.com/redir?resi...JEWCcmZXmKsI50

[Rabbit]

You can't assign a list object to a dataview object.

[tsanalista]

so in this case how can I do this kind of research in my Datagrid?

[tsanalista]

Could you explain how to obtain the same result in this example here?

Private Sub txtsearch_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles txtsearch.TextChanged
 
        Try
 
            Dim txtstring As String = Me.txtsearch.Text
 
            Dim dv As DataView = Me.DataGridView1.DataSource
 
            dv.RowFilter = "StudentsName LIKE '%" + txtstring + "%'"
 
            Me.DataGridView1.DataSource = dv
 
        Catch ex As Exception
            Throw ex
        End Try
 
    End Sub
 

[Rabbit]

Here's Microsoft's documentation on how to bind a DataView to a DataViewGrid.
http://msdn.microsoft.com/en-us/library/bb669070.aspx

[tsanalista]

Okay, thank you. But not exactly fills in the DataGrid I want. I want to make queries according what I type in the textbox.
Just like that I'm returning a List Of, I can not do this kind of query.

[tsanalista]

I want to take this research using BLL I created ... understand?
If I do it this way there is going to work. But would the design pattern that I am organizing.

[Rabbit]

I have no idea what you said in post #7.

That's just to bind a dataview to the dataviewgrid. You will still need to do your filtering after it.

[tsanalista]

Sorry, my English is weak, because I'm from Brazil.
About the project, how do I list the data using my BLL class that returns a List of Students?

Using this model below ..

 Public Sub AllStudents()
 
            _dset = Nothing
            Try
                _obj = New DALStudents()
                _dset = _obj.AllStudents()
 
                Dim objs As BLLStudents = Nothing
                _liststudents = New List(Of BLLStudents)
 
                For index As Integer = 0 To _dset.Tables(0).Rows.Count - 1
                    objs = New BLLStudents
                    objs.StudentsID = _dset.Tables(0).Rows(index)(0).ToString()
                    objs.CursoID = _dset.Tables(0).Rows(index)(1).ToString()
                    objs.EstudanteNome = _dset.Tables(0).Rows(index)(2).ToString()
                    objs.EstudanteEndereco = _dset.Tables(0).Rows(index)(3).ToString()
                    objs.Telefone = _dset.Tables(0).Rows(index)(4).ToString()
                    _liststudents.Add(objs)
                    objs = Nothing
                Next
 
            Catch ex As Exception
                Throw ex
            Finally
                _obj = Nothing
            End Try
 
        End Sub
 

[Rabbit]

Well, from your first post, it sounds like you're already listing the data. And it sounded like you were having problems filtering the data, not listing it. If you're actually having problems listing it, that's a completely different problem.

[tsanalista]

Exactly, in the first post, I can solve the problem. Now this would filter the data in the DataGrid using this model Crud as quoted above. But always give this error:

* Unable to cast object of type 'System.Collections.Generic.List `1 [BLL.BLL.Students.BLLStudents]' to type 'System.Data.DataView'.

[Rabbit]

You're confusing me. You just said you were having problems listing the data but now you say you're not having problems listing the data. So now we're back to the problem originally stated in the first post.

And the solution to that is in post #5 in the link to Microsoft's documentation on binding a dataview to a dataviewgrid. You have to correctly assign it before you can filter on it.