C# office-interop comobject excel-interop

如何将 COM 对象类型转换为 Excel.Checkbox 类型

发布于 2024-12-29 15:42:58 字数 966 浏览 2 评论 0原文

我正在向 Excel 添加一个复选框，但在将“System.__ComObject”类型的 COM 对象转换为接口类型“Microsoft.Office.Interop.Excel.CheckBox”时遇到问题，任何帮助将不胜感激！我正在使用 Visual Studio 2008 和 Office 2007 开发 Web 应用程序。错误发生在这一行：- chkBx = (Microsoft.Office.Interop.Excel.CheckBox)obj;

Microsoft.Office.Interop.Excel.OLEObjects objs = (Microsoft.Office.Interop.Excel.OLEObjects)mWSheet1.OLEObjects(System.Reflection.Missing.Value);

Microsoft.Office.Interop.Excel.OLEObject obj = objs.Add("Forms.CheckBox.1",
            System.Reflection.Missing.Value,
            System.Reflection.Missing.Value,
            false,
            false,
            System.Reflection.Missing.Value,
            System.Reflection.Missing.Value,
            234,
            234,
            108,
            21);

            Microsoft.Office.Interop.Excel.CheckBox chkBx;
            chkBx = (Microsoft.Office.Interop.Excel.CheckBox)obj;
            chkBx.Value = true;
            chkBx.Caption = "xyz";

原文

I am adding a checkbox to excel and i have issue casting a COM object of type 'System.__ComObject' to interface type 'Microsoft.Office.Interop.Excel.CheckBox', any help would be appreciated! I am working on web app using visual studio 2008 and office 2007. The error happens at this line :- chkBx = (Microsoft.Office.Interop.Excel.CheckBox)obj;

Microsoft.Office.Interop.Excel.OLEObjects objs = (Microsoft.Office.Interop.Excel.OLEObjects)mWSheet1.OLEObjects(System.Reflection.Missing.Value);

Microsoft.Office.Interop.Excel.OLEObject obj = objs.Add("Forms.CheckBox.1",
            System.Reflection.Missing.Value,
            System.Reflection.Missing.Value,
            false,
            false,
            System.Reflection.Missing.Value,
            System.Reflection.Missing.Value,
            234,
            234,
            108,
            21);

            Microsoft.Office.Interop.Excel.CheckBox chkBx;
            chkBx = (Microsoft.Office.Interop.Excel.CheckBox)obj;
            chkBx.Value = true;
            chkBx.Caption = "xyz";

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柒七 2025-01-05 15:42:58

在我看来，你无法投射它，因为它根本没有实现该接口。您可以使用 as 运算符检查 System.__ComObject 是否支持不进行强制转换的接口，从而引发异常，如下所述：如何：使用 Visual C# .NET 检查 COM 对象 (System.__ComObject) 的类型。

我想知道您是否使用了错误的方法将复选框添加到工作表中。不是更常见的方法是通过 <代码>Microsoft.Office.Tools.Excel.ControlCollection，如下所述：在运行时向 Office 文档添加控件。

如果您使用 ControlCollection，我认为您的代码最终会看起来像这样：

private void AddCheckBox()
{
    Worksheet vstoWorksheet = Globals.Factory.GetVstoObject(
        this.Application.ActiveWorkbook.Worksheets[1]);
    System.Windows.Forms.CheckBox checkbox = 
        new System.Windows.Forms.CheckBox();
    checkbox.Checked = true;
    checkbox.Text = "xyz"   
    vstoWorksheet.Controls.AddControl(234, 234, 108, 21, "checkbox1");
}

It looks to me like you can't cast it because it simply doesn't implement that interface. You can check if a System.__ComObject supports an interface without casting, and consequently throwing an exception, by using the as operator as described here: HOW TO: Check the Type of a COM Object (System.__ComObject) with Visual C# .NET.

I wonder if you are using the wrong method to add the checkbox to a worksheet. Isn't the more common method to go through Microsoft.Office.Tools.Excel.ControlCollection as described here: Adding Controls to Office Documents at Run Time.

If you used ControlCollection, I think your code would end up looking something like this:

private void AddCheckBox()
{
    Worksheet vstoWorksheet = Globals.Factory.GetVstoObject(
        this.Application.ActiveWorkbook.Worksheets[1]);
    System.Windows.Forms.CheckBox checkbox = 
        new System.Windows.Forms.CheckBox();
    checkbox.Checked = true;
    checkbox.Text = "xyz"   
    vstoWorksheet.Controls.AddControl(234, 234, 108, 21, "checkbox1");
}

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