打开一次Excel工作表并在其上迭代书写

本文关键字：书写 迭代 工作 Excel 一次 | 更新日期: 2023-09-27 17:56:52

我在 C# 中的应用程序在写入 Excel 工作表方面有一个概率。我的应用程序为其目的创建了 excel 工作表，并且没有写入其中。以下代码仅供参考。

class a
{
    void m()
    {
        b bee=new b();    
        Excel.Application oXL;
        Excel._Workbook oWB;
        b.write(oXL,oWB); //will be called multiple times
    }
}
class b
{
    static b() //declared static so that only once excel workbook with sheets will be     created
    {
        Excel._Application oXL = new Excel.Application();
        Excel._Workbook oWB = (Excel._Workbook)(oXL.Workbooks.Add(Type.Missing));
    }
    write( Excel.Application oXL, Excel._Workbook oWB)
    {
        oXL.Visible = true; //Here its throwing, Object reference not set to an instance of an  
                    //Object
    }
}

帮助将不胜感激，提前感谢！

打开一次Excel工作表并在其上迭代书写

我认为您希望具有以下代码：

class a
{
    b bee;
    public a()
    {
        bee = new b();
    }
    void m()
    {
        b.write(oXL,oWB); //will be called multiple times
    }
}
class b
{
    public b()
    {
        Excel._Application oXL = new Excel.Application();
        Excel._Workbook oWB = (Excel._Workbook)(oXL.Workbooks.Add(Type.Missing));
    }
    write()
    {
        oXL.Visible = true;
    }
}

然后，您需要确保仅创建所需 Excel 工作表的a实例。

你可以像这样使用它：

a aa = new a();
for(...)
    aa.m();

void m()
{
   b bee=new b();    
   Excel.Application oXL; // not initialized here!
   Excel._Workbook oWB;   // not initialized here!
   b.write(oXL,oWB);      // calling with uninitialized values! 
}

//...

class b
{
   static b() 
   {
       // here you declare two local variables not visible outside of your 
       // static constructor.
       Excel._Application oXL = new Excel.Application();
       Excel._Workbook oWB = (Excel._Workbook)(oXL.Workbooks.Add(Type.Missing));
   }
   // oXL here is a parameter, meaning it is completely different from
   // the local oXL in your static constructor
   void write( Excel.Application oXL, Excel._Workbook oWB)
   {
        oXL.Visible = true; 
   }
 }

我认为你想要的是将 oXL 和 oWB 声明为 b 类的成员变量。

void m()
{
   b bee=new b();    
   b.write();
}

//...

public class b
{
   Excel._Application oXL;
   Excel._Workbook oWB;
   public b() 
   {
       oXL = new Excel.Application();
       oWB = (Excel._Workbook)(oXL.Workbooks.Add(Type.Missing));
   }
   public void write()
   {
        // do something with cXL and oWB here
   }
 }
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