Vb.Net Delegates

[ganjasensation0098]

Hi guys.. I'm currently developing a system for a medical clinic. I want to know how (if ever) to implement delegates in my class. This is the sample of my class:

Public Class clsSite
    Inherits clsDatabase

    Private m_SiteId As String = String.Empty
    Private m_SiteDescription As String = String.Empty

    Public Property SiteId() As String
        Get
            Return m_SiteId
        End Get
        Set(ByVal value As String)
            m_SiteId = value
        End Set
    End Property

    Public Property SiteDescription() As String
        Get
            Return m_SiteDescription
        End Get
        Set(ByVal value As String)
            m_SiteDescription = value
        End Set
    End Property

    Public Function InsertSite(ByVal giveSiteId As String, ByVal giveSiteDescription As String) As Boolean
        Dim boolReturnValue As Boolean = True    
        Dim strSql As String = String.Empty

        m_SiteId = giveSiteId.Trim
        m_SiteDescription = giveSiteDescription.Trim.ToUpper

        strSql = "INSERT INTO `mf_site`" & _
                 "(`site_id`,`site_description`)" & _
                 "VALUES" & _
                 "(" & _
                 "'" & m_SiteId & "'," & _
                 "'" & m_SiteDescription & "'" & _
                 ")"

        If Not ExecuteQuery(strSql) Then boolReturnValue = False

        Return boolReturnValue
    End Function

    Public Function UpdateSite(ByVal giveSiteId As String, ByVal giveSiteDescription As String) As Boolean
        Dim boolReturnValue As Boolean = True    
        Dim strSql As String = String.Empty

        m_SiteId = giveSiteId.Trim
        m_SiteDescription = giveSiteDescription.Trim.ToUpper

        strSql = "UPDATE `mf_site` SET" & Space$(1) & _
                 "`site_description`='" & m_SiteDescription & "' " & _
                 "WHERE `site_id`='" & m_SiteId & "'"

        If Not ExecuteQuery(strSql) Then boolReturnValue = False

        Return boolReturnValue
    End Function

    Public Function DeleteSite(ByVal giveSiteId As String) As Boolean
        Dim boolReturnValue As Boolean = True        
        Dim strSql As String = String.Empty

        m_SiteId = giveSiteId.Trim

        strSql = "DELETE FROM mf_site" & " " & _
                 "WHERE site_id='" & m_SiteId & "'"

        If Not ExecuteQuery(strSql) Then boolReturnValue = False

        Return boolReturnValue
    End Function

    Public Function SearchSite(ByVal giveSiteId As String) As Boolean
        Dim boolReturnVale As Boolean = True        
        Dim strSql As String = String.Empty
        Try
            strSql = "SELECT * FROM mf_site WHERE site_id = '" & giveSiteId & "' ORDER BY site_id"
            Call ExecuteQuery(strSql)

            DbReader = DbCommand.ExecuteReader
            While DbReader.Read
                m_SiteId = DbReader("site_id")
                m_SiteDescription = DbReader("site_description")
            End While
        Catch ex As Exception
            Call ShowErrorMessage()
            boolReturnVale = False
        Finally
            DbReader.Close()
            DbCommand.Dispose()
        End Try
        Return boolReturnVale
    End Function

    Public Function GenerateSiteId() As String
        Dim strReturnValue As String = String.Empty
        Dim strSql As String = String.Empty
        Try
            strSql = "SELECT MAX(site_id) AS max_site_id FROM mf_site"
            Call ExecuteQuery(strSql)

            Dim strSiteId As String = String.Empty
            Dim iCtr As Integer = 1
            DbReader = DbCommand.ExecuteReader
            While DbReader.Read
                If Not IsDBNull(DbReader("max_site_id")) Then
                    iCtr = CInt(Right$(DbReader("max_site_id"), 10)) + 1
                End If
                strSiteId = "SID-" & Format$(iCtr, "0000000000")
                Exit While
            End While

            strReturnValue = strSiteId
        Catch ex As Exception
            Call ShowErrorMessage()
            strReturnValue = String.Empty
        Finally
            DbReader.Close()
            DbCommand.Dispose()
        End Try
        Return strReturnValue
    End Function

    Public Sub DisplaySiteList(ByVal objListView As ListView, Optional ByVal giveSearchString As String = "")        
        Dim strSql As String = String.Empty
        Try
            ' Adding ListView Columns
            objListView.GridLines = True
            objListView.View = View.Details

            objListView.Columns.Clear()
            objListView.Columns.Add("#", 50, HorizontalAlignment.Center)
            objListView.Columns.Add("Id", 100, HorizontalAlignment.Left)
            objListView.Columns.Add("Description", 155, HorizontalAlignment.Left)

            If giveSearchString.Trim = String.Empty Then
                strSql = "SELECT * FROM mf_site ORDER BY site_id"
            Else
                strSql = "SELECT *" & " "
                strSql = strSql & "FROM mf_site" & " "
                strSql = strSql & "WHERE 1 = 1" & " "
                strSql = strSql & "AND (site_description LIKE '%" & giveSearchString & "%'" & " "
                strSql = strSql & ") ORDER BY site_id"
            End If
            Call ExecuteQuery(strSql)

            Dim strSite(objListView.Columns.Count) As String
            Dim itmSite As ListViewItem
            Dim iCtr As Integer = 1

            objListView.Items.Clear()
            DbReader = DbCommand.ExecuteReader
            While DbReader.Read
                strSite(0) = iCtr
                strSite(1) = DbReader("site_id")
                strSite(2) = DbReader("site_description")
                itmSite = New ListViewItem(strSite)
                objListView.Items.Add(itmSite)
                iCtr = iCtr + 1
            End While

            ' autosize listview data by width
            For Each col As ColumnHeader In objListView.Columns
                col.Width = -2
            Next col
        Catch ex As Exception
            Call ShowErrorMessage()
        Finally
            DbReader.Close()
            DbCommand.Dispose()
        End Try
    End Sub

    Public Sub SiteComboList(ByVal objComboBox As ComboBox)        
        Dim strSql As String = String.Empty
        Try
            strSql = "SELECT `site_description` FROM mf_site ORDER BY site_id"
            Call ExecuteQuery(strSql)

            objComboBox.Items.Clear()
            DbReader = DbCommand.ExecuteReader
            While DbReader.Read
                objComboBox.Items.Add(DbReader("site_description"))
            End While
        Catch ex As Exception
            Call ShowErrorMessage()
        Finally
            DbReader.Close()
            DbCommand.Dispose()
        End Try
    End Sub

    Public Function GetSiteIdByDescription(ByVal giveSiteDescription As String) As String
        Dim strReturnValue As String = String.Empty
        Dim strSql As String = String.Empty
        Try
            strSql = "SELECT `site_id` FROM `mf_site` WHERE `site_description`='" & giveSiteDescription & "'"
            Call ExecuteQuery(strSql)

            DbReader = DbCommand.ExecuteReader
            While DbReader.Read
                strReturnValue = DbReader("site_id")
                Exit While
            End While
        Catch ex As Exception
            Call ShowErrorMessage()
            strReturnValue = String.Empty
        Finally
            DbReader.Close()
            DbCommand.Dispose()
        End Try
        Return strReturnValue
    End Function
End Class

[misson]

How much of the sample code you posted matters for your question? What do you need to know that MSDN doesn't tell you about delegates?