[VB6] 把VB6的程式碼包成DLL，讓C#呼叫

如果有些舊的VB6 的Code不想用人腦翻譯機把它翻成C#，

其實把舊的VB6 Code編成DLL來用，其實也蠻不錯的。


(1)首先開啟一個ActiveX DLL 專案

(2)定義好你的Class名稱

(3)寫好（貼好）程式碼

Public Function Add(ByVal A As Double, ByVal B As Double) As Double

Dim sum As Double

c = A + B


Add = c

End Function

(4)編成DLL （如果VB6裝在WIN7以上，開啟VB IDE時記得用管理者，否則編譯會出錯）

(5)在VS2015裡引用這個DLL

(6)撰寫程式碼 ，一樣會出現Func提示

(7)完整程式碼如下

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
      
        public Form1()
        {
            InitializeComponent();            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            VBFunc.VB_dll mVB6_func = new VBFunc.VB_dll();

            double sum = mVB6_func.Add(10.5, 1.8);

            label1.Text = sum.ToString();

        }
    }
}

(8)執行結果

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題外話

---

傳說中，VB6是原生的程式碼，會不會比C＃快呢，

我們來試試看在C＃與呼叫跟VB6 DLL的執行速度。

先來準備一個要RUN 1000000次的迴圈(執行環境為Win10 x64)

VB6 程式碼

Private Declare Function GetTickCount Lib "kernel32" () As Long
Private Sub Command1_Click()

Dim i As Long, temp As Long, temp1 As Long
    
temp = GetTickCount()

 For i = 0 To 9
 test
 
 Next
 
 
 temp1 = GetTickCount()
 Form1.Print temp1 - temp & "ms"
End Sub

Public Function test() As Long

Dim sum As Long

For i = 0 To 1000000

sum = 1 + 2

Next

tst = 10

End Function

VB6 執行數次，大約都在110～140ms

C＃程式碼

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
      
        public Form1()
        {
            InitializeComponent();            
        }

        private void button1_Click(object sender, EventArgs e)
        {
             VBFunc.VB_dll mVB6_func = new VBFunc.VB_dll();


            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();
            /*sw.Reset();
            sw.Start();
            for ( int i=0;i<10;i++)
            {
                long sum = mVB6_func.test();
            }            
            sw.Stop();
            string result1 = sw.Elapsed.TotalMilliseconds.ToString();
            label1.Text = result1;*/

            sw.Reset();
            sw.Start();
            for (int i = 0; i < 10; i++)
            {
                long sum = test();
            }
            sw.Stop();
            string result2 = sw.Elapsed.TotalMilliseconds.ToString();
            label2.Text = result2;


        }

        private long test()
        {
            long sum = 0;

            for (long i = 0; i < 1000000; i++)
            {
                sum = 1 + 2;
            }

            return 10;
        }
    }
}

C# 只要60ms就執行完了。

有點怪異，VB6慢好多，是不是Win10不喜歡它。

我來做個嘗試，把VB6編成DLL，讓C＃ 呼叫看看


如果我把剛才那段程式碼編成DLL讓C＃呼叫呢

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
      
        public Form1()
        {
            InitializeComponent();            
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Project1.Class1 class1 = new Project1.Class1();
            
        

            System.Diagnostics.Stopwatch sw2 = new System.Diagnostics.Stopwatch();
            sw2.Reset();
            sw2.Start();
            for (int i = 0; i < 10; i++)
            {
                long sum = test();
            }
            sw2.Stop();
            string result2 = sw2.Elapsed.TotalMilliseconds.ToString();
            label2.Text = "C# " + result2;

            System.Diagnostics.Stopwatch sw = new System.Diagnostics.Stopwatch();
            sw.Reset();
            sw.Start();
            for (int i = 0; i < 10; i++)
            {
                long sum = class1.test();
            }
            sw.Stop();
            string result1 = sw.Elapsed.TotalMilliseconds.ToString();
            label1.Text = "VB6 " + result1;

        }

        private long test()
        {
            long sum = 0;

            for (long i = 0; i < 1000000; i++)
            {
                sum = 1 + 2;
            }

            return 10;
        }
    }
}

雖然執行變快了，但是VB6在執行這段程式碼，仍然比C慢上一些。