How to make class library working from database server in windows application

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Windows

forms

I have Windows application created by VB.net and c# with 3 layer:
1-Data Access Layer : to connect and execute CRUD Operations using ADO.net
2-Class Library "BL": contains all Operation Functions like CreateStore, CreateTrans ...Etc
3- Windows forms projects UI: call Functions from reference Class Library "BL" to do all functionality, and All "BL" Dll(s) in the same Directory of "Binaries" that Contains Dll(s) of UI also.
My Issue is performance Issue because all of three layers on Client Machine to make any process must connect to Database server and execute the SQL Statement on Database server.
so , i need to move all Data Access layer and Class Library "BL" on the Same Database server or Application Server in the same location to avoid Connectivity Issues and left UI on Client Machine but still read the References of "BL".
thanks

What I have tried:

i tried to make windows Forms Project reference Path in Config file, but don't know how to make reference will read it in run time.

Explain:
1- UI Code vb.net or c# project (windows forms project(s) Or Class library project(s)) ,
so i have many User Interfaces execute the same BL function:

private void BtnSave_Click(object sender, EventArgs e)
        {
         StockControlBL StBL = new StockControlBL(); //create instance from BL 
         StBL.SaveStoreData(StoreParamters As Dictionary(Of String, Object)); // Call Function to create New Store
        }

we will build UI example project as "StoreTransUI.dll"
2- BL Code

'vb. project to make all BL Functions. for example create new store
 Public Function SaveStoreData(ByVal StoreParamters As Dictionary(Of String, Object)) as datatable
    private _dt as new datatable()
    private _Dl as new DataAccessLayer()
' some code of Validations 
    _dt =_dl.ExcuteQuery("SQLStoredProcedureName",SQLParamatersPrm()) 
    return _dt

end function

we will build BL example project as "StoreTransBL.dll"

3- Data Access Layer function:

 Private ConnectionString As String
<pre> Private Sub InitClass()

        Dim xmlDoc As New XmlDocument

        xmlDoc = New XmlDocument()
        Dim x As String = AppDomain.CurrentDomain.BaseDirectory
        Try
            Dim objReader As New System.IO.StreamReader(AppDomain.CurrentDomain.BaseDirectory & "app.config")
            Dim allString As String
            allString = objReader.ReadToEnd
           
          
            Dim sr As New System.IO.StringReader(allString )
            xmlDoc.Load(sr)


        Catch ex As Exception
            Throw (New Exception(ex.Message, ex.InnerException))
        End Try
     
        Dim xn As XmlNode

        xn = xmlDoc.SelectSingleNode("connectionstring")

        ConnectionString = xn.InnerText

    
    End Sub

Public Function ExecProc(ByVal StoredProcedure As String, ByVal Paramters As Dictionary(Of String, Object)) As DataTable
        Dim DtProc As DataTable
        Dim Dset As New DataSet
        Dim Trans As SqlTransaction = Nothing
        If ConnectionType = 0 Then
            Dim cnSQL As SqlConnection = New SqlConnection(ConnectionString)

            Dim cmdSel As SqlCommand = New SqlCommand(StoredProcedure, cnSQL)
            If cnSQL.State = ConnectionState.Closed Then
                cnSQL.Open()
            End If

            If cnSQL.State = ConnectionState.Open Then

                cmdSel.CommandType = CommandType.StoredProcedure
                Dim SqlAdapt As New SqlDataAdapter(cmdSel)
                If Not IsNothing(Paramters) Then
                    For Each param As KeyValuePair(Of String, Object) In Paramters
                        cmdSel.Parameters.Add(New SqlParameter(param.Key, param.Value))
                    Next
                End If
                Try
                    SqlAdapt.Fill(Dset)
                    Trans = cnSQL.BeginTransaction


                    Trans.Commit()
                Catch ex As Exception
                    Trans.Rollback()
                    cnSQL.Close()
                    cnSQL.Dispose()
                Finally
                    If cnSQL.State = ConnectionState.Open Then
                        cnSQL.Close()
                        cnSQL.Dispose()
                    End If
                End Try
            End If

        End If
        If Dset.Tables.Count > 0 Then
            DtProc = Dset.Tables(0)
            Dset.Tables.Clear()
            Return DtProc
        Else
            Return New DataTable
        End If

    End Function 

we will build DataAccessLayer example project as "DataAccessLayer.dll"
all layers files for example:(StoreTransUI.dll,StoreTransBL.dll,DataAccessLayer.Dll and App.config) in the same folder in client machine ,
actually the folder contains more than 700 files of UI and BL and DataAccessLayer.dll file and App.config file,
My issue is : i want to move All BL and Dataaccesslayer and App.config(to get SQL Database connection string ) in Database Server
and left Only UI on Client(s) machine to enhance connection Issues.
thanks