在.net中使用Com对象大家第一个反应就是在工程中引用Com对象,让vs.net自动生成一个包装过的.net类库。这种方法虽然方便,但是有很明显的缺点,最致命的就是开发的机器上安装的Com对象的版本比客户机器上安装的高,开发的程序无法正确的运行。如开发机器安装的是office 2003,而客户机器上的安装的确是office 2000、office xp甚至还有安装的是Office97,这种情况我想大家都深有体会吧?
在非托管语言如Delphi中可以通过CreateComObject来生成一个Com对象,然后再使用Variant对象去调用Com对象的属性、方法。可因C#是一种强类型的语言,他没有象Delphi中的Variant这中可变类型,因此只能通过反射去完成。
晚上心血来潮就封装了一个Variant对象来模拟一下Delphi中的Variant。
示例代码: //生成Excel对象
这样的方式是不是爽多了?那些讨厌的可选参数终于不用再写了!
Variant类源码:
其实Varaint类不光可以调用Com对象,对于托管对象也可以动态的创建和调用。
作者:小李菜刀
在非托管语言如Delphi中可以通过CreateComObject来生成一个Com对象,然后再使用Variant对象去调用Com对象的属性、方法。可因C#是一种强类型的语言,他没有象Delphi中的Variant这中可变类型,因此只能通过反射去完成。
晚上心血来潮就封装了一个Variant对象来模拟一下Delphi中的Variant。
示例代码: //生成Excel对象
using (Variant excel = Variant.CreateComInstance("Excel.Application"))
{
//显示Excel界面
excel["Visible"] = true;
//获取workBooks对象
using (Variant workBooks = Variant.CreateInstance(excel["Workbooks"]))
{
//建立一个Workbook
using (Variant workBook = Variant.CreateInstance(workBooks.InvokeMethod("Add")))
{
for (int i = 1; i < 10; i++)
{
for (int j = 1; j < 10; j++)
{
//根据指定的索引获得一个单元格
using (Variant cell = Variant.CreateInstance(excel["Cells", i, j]))
{
//设置单元格的值
cell["Value"] = i * j;
Console.WriteLine(cell["Value"]);
}
}
}
}
}
//excel.InvokeMethod("Quit");
}
{
//显示Excel界面
excel["Visible"] = true;
//获取workBooks对象
using (Variant workBooks = Variant.CreateInstance(excel["Workbooks"]))
{
//建立一个Workbook
using (Variant workBook = Variant.CreateInstance(workBooks.InvokeMethod("Add")))
{
for (int i = 1; i < 10; i++)
{
for (int j = 1; j < 10; j++)
{
//根据指定的索引获得一个单元格
using (Variant cell = Variant.CreateInstance(excel["Cells", i, j]))
{
//设置单元格的值
cell["Value"] = i * j;
Console.WriteLine(cell["Value"]);
}
}
}
}
}
//excel.InvokeMethod("Quit");
}
这样的方式是不是爽多了?那些讨厌的可选参数终于不用再写了!
Variant类源码:
Using directives
class Variant : IDisposable
{
Variant() { }
object _obj;
Type _objType;
bool _isComObj = false;
public static Variant CreateComInstance(string progID)
{
Variant variant = new Variant();
variant._objType = Type.GetTypeFromProgID(progID);
variant._obj = Activator.CreateInstance(variant._objType);
variant._isComObj = true;
return variant;
}
public static Variant CreateInstance(string objectTypeName)
{
Variant variant = new Variant();
variant._objType = Type.GetType(objectTypeName);
variant._obj = Activator.CreateInstance(variant._objType);
return variant;
}
public static Variant CreateInstance(object obj)
{
Variant variant = new Variant();
variant._objType = obj.GetType();
variant._obj = obj;
variant._isComObj = obj.GetType().ToString() == "System.__ComObject";
return variant;
}
public int ReleaseComObject()
{
try
{
if (_isComObj)
return Marshal.ReleaseComObject(_obj);
else
throw new Exception("_obj is not com Object");
}
catch
{
throw;
}
}
public object InvokeMethod(string methodName,params object[] parameters)
{
try
{
return _objType.InvokeMember(methodName,
BindingFlags.InvokeMethod,
null, _obj, parameters);
}
catch
{
throw;
}
}
public object GetPropertyValue(string propertyName, params object[] parameters)
{
try
{
return _objType.InvokeMember(propertyName,
BindingFlags.GetProperty,
null, _obj, parameters);
}
catch
{
throw;
}
}
public void SetPropertyValue(string propertyName, object value, params object[] parameters)
{
if (value as DBNull != null)
value = null;
string s = value as string;
if (s != null && s.Length == 0)
value = null;
if (_isComObj)
{
try
{
object[] args = new object[parameters.Length + 1];
Array.Copy(parameters, 0, args, 1, parameters.Length);
args[0] = value;
_objType.InvokeMember(propertyName,
BindingFlags.SetProperty,
null, _obj, args);
}
catch
{
throw;
}
return;
}
PropertyInfo pi = _objType.GetProperty(propertyName);
if (pi != null)
{
if (pi.CanWrite)
{
try
{
pi.SetValue(_obj, null == value ?
null :
(pi.PropertyType.IsInterface ?
value :
Convert.ChangeType(value, pi.PropertyType)
),
parameters);
}
catch (Exception E)
{
throw new Exception(String.Format("设置属性{0}时出错!属性的类型是{1}值的类型是{2} 错误信息:{3}", pi.Name, pi.PropertyType.FullName, value.GetType().FullName, null == E.InnerException ? E.Message : E.InnerException.Message));
}
}
else
throw new Exception(pi.PropertyType.ToString());
}
else
throw new Exception(String.Format("{0}属性未在{1}中定义!", pi.Name, _obj.GetType().FullName));
}
public object this[string propertyName, params object[] parameters]
{
get { return GetPropertyValue(propertyName, parameters); }
set { SetPropertyValue(propertyName, value, parameters); }
}
IDisposable Members
}
class Variant : IDisposable
{
Variant() { }
object _obj;
Type _objType;
bool _isComObj = false;
public static Variant CreateComInstance(string progID)
{
Variant variant = new Variant();
variant._objType = Type.GetTypeFromProgID(progID);
variant._obj = Activator.CreateInstance(variant._objType);
variant._isComObj = true;
return variant;
}
public static Variant CreateInstance(string objectTypeName)
{
Variant variant = new Variant();
variant._objType = Type.GetType(objectTypeName);
variant._obj = Activator.CreateInstance(variant._objType);
return variant;
}
public static Variant CreateInstance(object obj)
{
Variant variant = new Variant();
variant._objType = obj.GetType();
variant._obj = obj;
variant._isComObj = obj.GetType().ToString() == "System.__ComObject";
return variant;
}
public int ReleaseComObject()
{
try
{
if (_isComObj)
return Marshal.ReleaseComObject(_obj);
else
throw new Exception("_obj is not com Object");
}
catch
{
throw;
}
}
public object InvokeMethod(string methodName,params object[] parameters)
{
try
{
return _objType.InvokeMember(methodName,
BindingFlags.InvokeMethod,
null, _obj, parameters);
}
catch
{
throw;
}
}
public object GetPropertyValue(string propertyName, params object[] parameters)
{
try
{
return _objType.InvokeMember(propertyName,
BindingFlags.GetProperty,
null, _obj, parameters);
}
catch
{
throw;
}
}
public void SetPropertyValue(string propertyName, object value, params object[] parameters)
{
if (value as DBNull != null)
value = null;
string s = value as string;
if (s != null && s.Length == 0)
value = null;
if (_isComObj)
{
try
{
object[] args = new object[parameters.Length + 1];
Array.Copy(parameters, 0, args, 1, parameters.Length);
args[0] = value;
_objType.InvokeMember(propertyName,
BindingFlags.SetProperty,
null, _obj, args);
}
catch
{
throw;
}
return;
}
PropertyInfo pi = _objType.GetProperty(propertyName);
if (pi != null)
{
if (pi.CanWrite)
{
try
{
pi.SetValue(_obj, null == value ?
null :
(pi.PropertyType.IsInterface ?
value :
Convert.ChangeType(value, pi.PropertyType)
),
parameters);
}
catch (Exception E)
{
throw new Exception(String.Format("设置属性{0}时出错!属性的类型是{1}值的类型是{2} 错误信息:{3}", pi.Name, pi.PropertyType.FullName, value.GetType().FullName, null == E.InnerException ? E.Message : E.InnerException.Message));
}
}
else
throw new Exception(pi.PropertyType.ToString());
}
else
throw new Exception(String.Format("{0}属性未在{1}中定义!", pi.Name, _obj.GetType().FullName));
}
public object this[string propertyName, params object[] parameters]
{
get { return GetPropertyValue(propertyName, parameters); }
set { SetPropertyValue(propertyName, value, parameters); }
}
IDisposable Members
}
其实Varaint类不光可以调用Com对象,对于托管对象也可以动态的创建和调用。
作者:小李菜刀