?Imports System.Data
Imports System.Data.SqlClient       '新增命名空間 for SQL Server

Public Class ChagePwd

    Dim TableName As String = "Login"
    Dim errorMsg As String
    Dim LoginErrorCounter As Integer
    Dim ConnString As String


    Dim conn As SqlConnection
    Dim cmd As SqlCommand
    Dim dr As SqlDataReader
    Dim da As SqlDataAdapter

    Dim UserID As String
    Dim OldPwd As String
    Dim NewPwd As String
    Dim CheckNewPwd As String

#Region "資料庫初始化"

    ''' <summary>
    ''' 資料庫初始化
    ''' </summary>
    Public Sub InitDB()

        ConnString = SQLConnectionString()
        conn = New SqlConnection(ConnString)
        conn.Open()

    End Sub

#End Region

    '確定
    Private Sub btn_OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_OK.Click

        UserID = WinEvents.LoginUserID
        OldPwd = txt_OldPwd.Text
        NewPwd = txt_NewPwd.Text
        CheckNewPwd = txt_CheckNewPwd.Text

        If CheckField() Then

            If RunChagePwd(UserID, OldPwd, NewPwd) Then
                Me.Close()
            End If

        End If

    End Sub

#Region "欄位檢查"

    ''' <summary>
    ''' 欄位檢查
    ''' </summary>

    Public Function CheckField() As Boolean

        If (txt_OldPwd.Text = "") Then

            MessageBox.Show("[舊密碼]不得為空白;", "欄位檢查", MessageBoxButtons.OK, MessageBoxIcon.Exclamation, MessageBoxDefaultButton.Button1)
            txt_OldPwd.Text = ""
            txt_NewPwd.Text = ""
            txt_CheckNewPwd.Text = ""

            txt_OldPwd.Focus()
            Return False

        End If

        If (txt_NewPwd.Text = "") Then

            MessageBox.Show("[新密碼]不得為空白;", "欄位檢查", MessageBoxButtons.OK, MessageBoxIcon.Exclamation, MessageBoxDefaultButton.Button1)
            txt_OldPwd.Text = ""
            txt_NewPwd.Text = ""
            txt_CheckNewPwd.Text = ""

            txt_NewPwd.Focus()
            Return False

        End If

        If (txt_CheckNewPwd.Text = "") Then

            MessageBox.Show("[確認密碼]不得為空白;", "欄位檢查", MessageBoxButtons.OK, MessageBoxIcon.Exclamation, MessageBoxDefaultButton.Button1)
            txt_OldPwd.Text = ""
            txt_NewPwd.Text = ""
            txt_CheckNewPwd.Text = ""

            txt_CheckNewPwd.Focus()
            Return False

        End If

        If (txt_NewPwd.Text <> txt_CheckNewPwd.Text) Then

            MessageBox.Show("[新密碼]與[確認密碼]必須一樣;", "欄位檢查", MessageBoxButtons.OK, MessageBoxIcon.Exclamation, MessageBoxDefaultButton.Button1)
            txt_OldPwd.Text = ""
            txt_NewPwd.Text = ""
            txt_CheckNewPwd.Text = ""

            txt_NewPwd.Focus()
            Return False

        End If

        Return True

    End Function

#End Region

#Region "執行更改動作"

    Public Function RunChagePwd(ByVal UserId As String, ByVal OldPwd As String, ByVal NewPwd As String) As Boolean

        If UpdatePwd(UserId, OldPwd, NewPwd) Then

            If VerifyPwd(UserId,  NewPwd) Then

                MessageBox.Show("使用者密碼變更完成^_^")

                txt_OldPwd.Text = ""
                txt_NewPwd.Text = ""
                txt_CheckNewPwd.Text = ""

                Return True
            Else

                MessageBox.Show("使用者密碼變更失敗>.<")

                Return False

            End If

            Return True
        Else

            MessageBox.Show("使用者密碼變更失敗>.<")

            Return False

        End If

    End Function

#End Region

#Region "更新密碼"

    ''' <summary>
    ''' 更新密碼
    '''</summary>
    Public Function UpdatePwd(ByVal UserId As String, ByVal OldPwd As String, ByVal NewPwd As String) As Boolean

        InitDB()

        Dim updateCmd As String
        Dim i As Integer = 0

        updateCmd = "UPDATE " + TableName + " SET UserPwd='" + NewPwd + "'"
        updateCmd = updateCmd + " WHERE UserID='" + UserId + "'"

        Try

            cmd = New SqlCommand(updateCmd, conn)
            i = cmd.ExecuteNonQuery()  '若沒有任何異動則回傳0
            conn.Close()

            If (i = 1) Then
                Return True
            Else
                Return False
            End If

        Catch ex As Exception

            errorMsg = ex.Message
            conn.Close()
            Return False

        End Try

        Return False

    End Function

#End Region

#Region "驗證帳號與密碼"

    Public Function VerifyPwd(ByVal UserID As String, ByVal UserPwd As String) As Boolean

        InitDB()

        Dim selectCmd As String

        selectCmd = "Select * From " + TableName + " Where UserID='" + UserID + "' And UserPwd='" + UserPwd + "'"
        '注意：欄位名稱不可為Password

        Try
            cmd = New SqlCommand(selectCmd, conn)
            dr = cmd.ExecuteReader()
            If (dr.Read()) Then
                conn.Close()
                Return True
            Else
                conn.Close()
                Return False
            End If

        Catch ex As Exception

            errorMsg = ex.Message
            conn.Close()
            Return False

        End Try

    End Function

#End Region

    Private Sub btn_Cancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_Cancel.Click
        Me.Close()
    End Sub

End Class