{"id":384,"date":"2005-04-27T16:18:08","date_gmt":"2005-04-27T08:18:08","guid":{"rendered":"http:\/\/blog.axqd.net\/?p=384"},"modified":"2005-04-27T16:18:08","modified_gmt":"2005-04-27T08:18:08","slug":"basic-question-of-c-sharp","status":"publish","type":"post","link":"https:\/\/blog.axqd.net\/?p=384","title":{"rendered":"\u5173\u4e8eC#\u4e00\u4e2a\u57fa\u7840\u95ee\u9898\u7684\u521d\u6b65\u63a2\u67e5"},"content":{"rendered":"

\u5173\u4e8eC#\u4e00\u4e2a\u5f31\u5f31\u95ee\u9898\u7684\u521d\u6b65\u63a2\u67e5<\/p>\n

\u5728\u4e66\u4e0a\u770b\u5230\u8fd9\u6837\u4e00\u4e2a\u4f8b\u5b50\uff1a<\/p>\n

\u5df2\u77e5\uff1a
\ninterface IControl
\n{
\n void Paint();
\n}
\nclass Control : IControl
\n{
\n public void Paint(){ ... }
\n}
\nclass TextBox : Control
\n{
\n new public void Paint(){ ... }
\n}<\/code>
\n\u95ee:
\nIControl it = new TextBox();
\nit.Paint(); \/\/\u8c03\u7528\u54ea\u4e2aPaint()?<\/code><\/p>\n

\u4e66\u4e0a\u7684\u7ed3\u8bba\u662fControl::Paint(),\u5e76\u4e14\u5439\u4e86\u4e00\u901a\u4ec0\u4e48\u6ca1\u6709virtual\u5173\u952e\u5b57\u6216\u8005\u8ba9TextBox\u76f4\u63a5\u7ee7\u627f\u81f3IControl\u5c31\u662f\u9759\u6001\u51b3\u8bae\uff0c\u4ec0\u4e48\u5982\u679cControl::Paint()\u52a0\u4e0avirtual\u53c8\u600e\u4e48\u600e\u4e48\uff0c\u5982\u679cTextBox::Paint()\u53bb\u6389new\u53c8\u600e\u4e48\u600e\u4e48,\u611f\u89c9\u751a\u662f\u7e41\u7410\u3001\u590d\u6742\u548c\u591a\u53d8\uff0c\u8ba9\u4eba\u5982\u5760\u4e07\u4e08\u6df1\u6e0a\uff0c\u4e07\u52ab\u4e0d\u590d…(- -)<\/p>\n

\u5c31\u6211\u539f\u6765\u4eceC++\u5e26\u6765\u7684\u7406\u89e3\uff1aIControl\u662f\u4e2ainterface\uff0c\u5176\u5b9e\u9690\u542bIControl::Paint()\u662fabstract \u4ee5\u53ca public\uff0c\u53ea\u662f\u4e0d\u80fd\u663e\u5f0f\u5199\u51fa\uff1b\u6240\u4ee5\u6210\u5458\u51fd\u6570\u7684\u8c03\u7528\u51b3\u8bae\u5e94\u8be5\u662f\u8fd0\u884c\u671f\u5b8c\u6210\uff0c\u4e5f\u5c31\u662f\u8bf4\u4e3aTextBox::Paint();<\/p>\n

\u5b9e\u9645\u4e0a\u673a\u6d4b\u8bd5\u7ed3\u679c\uff0c\u4ee4\u4eba\u6c57\u989c\uff0c\u4ed6\u7684\u7ed3\u679c\u7684\u786e\u662f\u6b63\u786e\u7684\uff0c\u4f46\u662f\u4ed6\u7684\u540e\u7eed\u6240\u6709\u89e3\u91ca\u90fd\u662f\u9519\u8bef\u7684\uff1b\u4e0d\u7ba1\u5982\u4f55\u52a0virtual\u3001\u53bb\u6389new\uff0c\u6700\u540e\u7684\u7ed3\u679c\u90fd\u662f\u4e00\u4e2a—Control::Paint(),\u7a0b\u5e8f\u4ee3\u7801\u5982\u4e0b\uff1a
\nusing System;
\nnamespace TestInterface
\n{
\n interface IControl
\n {
\n void Paint();
\n }
\n class Control : IControl
\n {
\n public void Paint()
\n {
\n Console.WriteLine(\"Control::Paint()\");
\n }
\n }
\n \/\/\/ <\/p>\n

\n \/\/\/ TextBox \u7684\u6458\u8981\u8bf4\u660e\u3002
\n \/\/\/ <\/summary>\n

class TextBox : Control
\n {
\n new public void Paint()
\n {
\n Console.WriteLine(\"TextBox::Paint()\");
\n }
\n }
\n \/\/\/ <\/p>\n

\n \/\/\/ TestInterface \u7684\u6458\u8981\u8bf4\u660e\u3002
\n \/\/\/ <\/summary>\n

class TestInterface
\n {
\n \/\/\/ <\/p>\n

\n \/\/\/ \u5e94\u7528\u7a0b\u5e8f\u7684\u4e3b\u5165\u53e3\u70b9\u3002
\n \/\/\/ <\/summary>\n

[STAThread]
\n static void Main(string[] args)
\n {
\n \/\/
\n \/\/ TODO: \u5728\u6b64\u5904\u6dfb\u52a0\u4ee3\u7801\u4ee5\u542f\u52a8\u5e94\u7528\u7a0b\u5e8f
\n \/\/
\n IControl it = new TextBox();
\n it.Paint();
\n }
\n }
\n}<\/code><\/p>\n

\u5982\u679c\u53bb\u6389new\u5f53\u7136\u4ec5\u4ec5\u4f1a\u5bfc\u81f4\u8b66\u544a\uff0c\u5b9e\u9645\u4e0a\u8fd8\u662f\u8986\u76d6\u3002<\/p>\n

\u4e66\u4e2d\u8fd8\u63d0\u5230\u201c\u6211\u4eec\u7684\u8bef\u89e3\u6765\u81ea\u4e00\u4e2a\u5047\u8bbe\uff1aControl::Paint()\u88ab\u81ea\u52a8\u89c6\u4e3avitrual\u201d,\u6839\u636e\u5b9e\u9645\u4e0a\u673a\u6d4b\u8bd5\uff0c\u8fd9\u4e2a\u5047\u8bbe\u7684\u786e\u662f\u6210\u7acb\u7684\uff0c\u800c\u4e0d\u662f\u4ec0\u4e48\u8bef\u89e3\uff0c\u81f3\u4e8e\u52a0\u4e0avirtual\u548c\u53bb\u6389virtual\u6240\u5e26\u6765\u7684\u533a\u522b\u4ec5\u4ec5\u5728\u4e8e\u662f\u5426\u52a0\u5165\u5173\u952e\u5b57final\u3002\u5982\u679c\u6ca1\u6709\u52a0\u4e0a\u4e86virtual\uff0c\u90a3\u4e48Control::Paint()\u4f1a\u81ea\u52a8\u89c6\u4e3afinal(IL\u4e2d)\uff0c\u6709\u4f8b\u4e3a\u8bc1\uff1a<\/p>\n

Contorl::Paint()
\n.method public hidebysig newslot virtual final \/\/\u5982\u679c\u52a0\u4e0avitrual\u5219\u8fd9\u91cc\u53bb\u6389final
\n instance void Paint() cil managed
\n{
\n \/\/ \u4ee3\u7801\u5927\u5c0f 11 (0xb)
\n .maxstack 1
\n IL_0000: ldstr \"Control::Paint()\"
\n IL_0005: call void [mscorlib]System.Console::WriteLine(string)
\n IL_000a: ret
\n} \/\/ end of method Control::Paint
\nTextBox::Paint()
\n.method public hidebysig instance void Paint() cil managed
\n{
\n \/\/ \u4ee3\u7801\u5927\u5c0f 11 (0xb)
\n .maxstack 1
\n IL_0000: ldstr \"TextBox::Paint()\"
\n IL_0005: call void [mscorlib]System.Console::WriteLine(string)
\n IL_000a: ret
\n} \/\/ end of method TextBox::Paint<\/code><\/p>\n

\u800c\u5728Main()\u4e2d\u4ec5\u662f\u7b80\u5355\u8c03\u7528IControl::Paint()<\/p>\n

.method private hidebysig static void Main(string[] args) cil managed
\n{
\n .entrypoint
\n .custom instance void [mscorlib]System.STAThreadAttribute::.ctor() = ( 01 00 00 00 )
\n \/\/ \u4ee3\u7801\u5927\u5c0f 13 (0xd)
\n .maxstack 1
\n .locals init ([0] class TestInterface.IControl it)
\n IL_0000: newobj instance void TestInterface.TextBox::.ctor()
\n IL_0005: stloc.0
\n IL_0006: ldloc.0
\n IL_0007: callvirt instance void TestInterface.IControl::Paint()
\n IL_000c: ret
\n} \/\/ end of method TestInterface::Main<\/code><\/p>\n

===== \u534e\u4e3d\u7684\u5206\u5272\u7ebf =====
\n\u5475\u5475,\u4ee5\u4e0a\u5c31\u662f\u6211\u521d\u6b65\u7684\u5206\u6790,\u7279\u522b\u6df7\u4e71,\u4e0d\u8981\u89c1\u7b11,\u4e0b\u9762\u6211\u505a\u4e2a\u603b\u7ed3(\u4e2a\u4eba\u610f\u89c1\u3001\u4ec5\u4f9b\u53c2\u8003)<\/p>\n

\u539f\u6765\u7684C++\u5230C#\uff0c\u5728\u51fd\u6570\u91cd\u8f7d\u8fd9\u4e00\u5757\u6709\u4e00\u4e2a\u5f88\u660e\u663e\u7684\u533a\u522b\uff0c\u90a3\u5c31\u662foverride\u5173\u952e\u5b57\u3002\u5982\u679c\u91cd\u8f7d\u5fc5\u987b\u663e\u5f0f\u7684\u6307\u660eoverride\u5173\u952e\u5b57\uff0c\u5982\u679c\u6ca1\u6709\uff0c\u5c06\u9690\u85cf\u57fa\u7c7b\u6210\u5458\u3002\u8fd9\u70b9\u662f\u5f88\u81ea\u7136\u7684\uff0c\u4f46\u662f\u672c\u4f8b\u7684\u7279\u522b\u4e4b\u5904\u5728\u4e8einterface\u7684\u5f15\u5165\u3002<\/p>\n

—– interface —–
\ninterface\u9ed8\u8ba4\u4e3aabstract\u7c7b\uff0c\u4f46\u662f\u548c\u666e\u901aabstract\u7c7b\u4e0d\u540c\u7684\u662f\uff0c\u4ed6\u5e76\u6ca1\u6709\u6d3e\u751f\u81eaSystem.Object\uff1b\u5176\u5185\u63a5\u53e3\u4e5f\u9ed8\u8ba4\u4e3aabstract virtual\u5982\u4e0b\uff1a<\/p>\n

.class interface private abstract auto ansi IControl
\n{
\n} \/\/ end of class IControl
\n.method public hidebysig newslot abstract virtual
\n instance void Paint() cil managed
\n{
\n} \/\/ end of method IControl::Paint<\/code><\/p>\n

\u4e4b\u6240\u4ee5interface\u88ab\u9ed8\u8ba4\u4e3apublic(\u6307\u5176\u5185\u63a5\u53e3\uff0c\u800cinterface\u672c\u8eab\u53ef\u4ee5\u4e0d\u4e3apublic)\uff0cabstract\u5c31\u4e0d\u7528\u89e3\u91ca\u4e86\uff0c\u4f46\u662f\u660e\u793a\u51fa\u6765\u53cd\u800c\u4f1a\u51fa\u9519\uff1b
\n—– interface end —–<\/p>\n

—– interface implement —–
\n.class private auto ansi beforefieldinit Control
\n extends [mscorlib]System.Object
\n implements TestInterface.IControl
\n{
\n} \/\/ end of class Control
\n.method public hidebysig newslot virtual final \/\/\u5982\u679c\u52a0\u4e0avitrual\u5219\u8fd9\u91cc\u53bb\u6389final
\n instance void Paint() cil managed
\n{
\n \/\/ \u4ee3\u7801\u5927\u5c0f 11 (0xb)
\n .maxstack 1
\n IL_0000: ldstr \"Control::Paint()\"
\n IL_0005: call void [mscorlib]System.Console::WriteLine(string)
\n IL_000a: ret
\n} \/\/ end of method Control::Paint<\/code><\/p>\n

\u8fd9\u91cc\u592a\u6709\u8da3\u4e86(- -,\u8fc7\u5206\u4e86…\u8fd8\u662f\u8bf4\u7a0d\u5fae\u6709\u70b9\u610f\u601d)interface\u63a5\u53e3\u7684\u5b9e\u73b0\u4f1a\u5728IL\u4e2d\u81ea\u52a8\u52a0\u4e0avirtual\u5173\u952e\u5b57\uff0c\u800c\u4e0d\u50cf\u521a\u624d\u4e66\u4e0a\u8bf4\u7684\uff0c\u4ec0\u4e48\u8bef\u89e3\uff0c\u8fd9\u662f\u4e3a\u4ec0\u4e48\u5462\uff1f\u56e0\u4e3a\u5982\u679c\u50cf\u672c\u4f8b\u4e2d\u4e00\u6837\uff0c\u7528IControl\u8c03\u7528Paint()\uff0c\u800cIControl\u672c\u8eab\u662f\u4e0d\u4f1a\u5b9e\u73b0Paint()\u7684\uff0c\u6240\u4ee5\u4ed6\u7684\u5b9e\u73b0\u5fc5\u987b\u5728IL\u4e2d\u4ee5virtual\u5173\u952e\u5b57\u6807\u660e\uff0c\u8ba9\u52a8\u6001\u51b3\u8bae\u7684\u65f6\u5019\uff0c\u80fd\u591f\u8003\u8651\u5230\u8fd9\u4e2a\u5b9e\u73b0\uff0c\u4e0d\u7136IControl::Paint()\u7684\u8c03\u7528\u5c31\u4f1a\u51fa\u95ee\u9898\u3002<\/p>\n

\u81f3\u4e8e\u8fd9\u91cc\u63d0\u5230\u7684final\uff0c\u4e5f\u662finterface implement\u6bd4\u8f83\u72ec\u7279\u7684\u4e00\u70b9\u3002override\u4f1a\u4f7f\u5f97\u672c\u8eab\u91cd\u8f7d\u57fa\u7c7b\u6210\u5458\uff0c\u5e76\u4e14\u672c\u8eab\u6210\u4e3avirtual\uff0c\u6240\u4ee5\u81ea\u5df1\u7684\u5b50\u7c7b\u4e5f\u53ef\u4ee5\u91cd\u8f7d\u81ea\u5df1\u3002\u5728\u7a0b\u5e8f\u4e2d\uff0c\u82e5\u60f3\u91cd\u8f7d\u57fa\u7c7b\u6210\u5458\uff0c\u4f46\u53c8\u4e0d\u60f3\u8ba9\u5b50\u7c7b\u7ee7\u7eed\u91cd\u8f7d\uff0c\u5c31\u4f1a\u4f7f\u7528override sealed\u5173\u952e\u5b57\uff0c\u8fd9\u91ccIL\u4e2d\u7684final\u5173\u952e\u5b57\u5b9e\u9645\u4e0a\u5c31\u662f\u6307\u7684sealed\u3002<\/p>\n

\u7531\u6b64\uff0c\u6211\u4eec\u4e00\u822c\u5199\u4e00\u4e2a\u51fd\u6570:<\/p>\n

public void foo();<\/code><\/p>\n

\u5b50\u7c7b\u90fd\u65e0\u6cd5override\uff0c\u9664\u975e\u51fd\u6570\u6539\u4e3a\uff1a<\/p>\n

virtual void foo();<\/code><\/p>\n

\u4f46\u662f\u8fd9\u91cc\u7531\u4e8einterface implement\u672c\u8eab\u9700\u8981\u7533\u660e\u4e3aoverride(IL\u4e2d\u4ecd\u4e3avirtual)\uff0c\u6240\u4ee5\u4e3a\u4e86\u5ef6\u7eed\u60ef\u4f8b\uff0c\u7528sealed(IL\u4e2d\u4e3afinal)\u5c01\u95ed\u4e4b\uff0c\u9664\u975e\u4f60\u663e\u793a\u7684\u6307\u793avirtual\uff0c\u8fd9\u6837\u5c31\u548c\u6211\u4eec\u901a\u5e38\u7684\u89c2\u5ff5\u4fdd\u6301\u4e00\u81f4\u9e1f~~~~
\n—– interface implement end —–<\/p>\n

—– extended classes —–
\n.class private auto ansi beforefieldinit TextBox
\n extends TestInterface.Control
\n{
\n} \/\/ end of class TextBox
\nextends TestInterface.Control
\n.method public hidebysig instance void Paint() cil managed
\n{
\n \/\/ \u4ee3\u7801\u5927\u5c0f 11 (0xb)
\n .maxstack 1
\n IL_0000: ldstr \"TextBox::Paint()\"
\n IL_0005: call void [mscorlib]System.Console::WriteLine(string)
\n IL_000a: ret
\n} \/\/ end of method TextBox::Paint<\/code><\/p>\n

\u8fd9\u91cc\u4e0d\u7ba1\u4f60\u662f\u5426\u91c7\u7528new\u5173\u952e\u5b57\uff0c\u5b9e\u9645\u4e0a\u90fd\u8d77\u5230\u4e86\u8986\u76d6\u7684\u4f5c\u7528\uff0c\u53ea\u662f\u5982\u679c\u6ca1\u6709new\u5173\u952e\u5b57\u4f1a\u5f15\u53d1\u8b66\u544a\uff0c\u63d0\u9192\u4f60\u662f\u5426\u786e\u5b9e\u662f\u60f3\u8986\u76d6\uff0c\u5982\u679c\u4f60\u60f3\u5173\u95ed\u8b66\u544a\uff0c\u5c31\u5fc5\u987b\u663e\u793a\u7684\u544a\u8bc9\u7f16\u8bd1\u5668\u6211\u60f3\u8986\u76d6—\u5c31\u662f\u4f7f\u7528new\u5173\u952e\u5b57\u3002<\/p>\n

\u503c\u5f97\u4e00\u63d0\u7684\u6709\u4e24\u70b9\uff1a
\n1\u3001\u5982\u679c\u7a0b\u5e8f\u4e2d\u76f4\u63a5\u5199virtual\u800c\u4e0d\u7528override\uff0c\u5176\u5b9e\u8fd8\u662f\u8986\u76d6\u3002\u53ef\u4ee5\u4eceIL\u4e2d\u770b\u51fa\uff1a
\n\u7a0b\u5e8f<->IL
\nvirtual<->newslot virtual
\noverride<->virtual
\n2\u3001\u5982\u679c\u8fd9\u4e2a\u7c7b\u76f4\u63a5\u591a\u91cd\u7ee7\u627fIControl\uff0c\u50cf\u8fd9\u6837\uff1a
\n class TextBox : Control, IControl
\n {
\n ...
\n }<\/code>
\n\u5b9e\u9645\u4e0a\u8fd9\u4e2a\u7c7b\u5c31\u4e0d\u518d\u5c5e\u4e8eextended classes\u4e86\uff0c\u800c\u662finterface implement\u3002\u7531\u4e8e\u5bf9\u4e8einterface implement\u7684\u9009\u62e9\u662fvirtual\u7684\uff0c\u6240\u4ee5\u5f88\u81ea\u7136\u4f1a\u8c03\u7528TextBox::Paint();
\n—– extended classes end —–<\/p>\n

\u5982\u679c\u4ee5\u4e0a\u7684\u8ba8\u8bba\u6b63\u786e\uff0c\u672c\u4f8b\u5c31\u5f88\u597d\u89e3\u91ca\u9e1f~~~<\/p>\n

IControl::Paint()\u7531\u4e8e\u662fvirtual\uff0c\u4ed6\u4f1a\u5148\u884c\u5bfb\u627e\u53ef\u884c\u51fd\u6570\uff0c\u518d\u8fdb\u884c\u6700\u4f73\u51b3\u8bae\uff1b<\/p>\n

\u7531\u4e8enew\u5173\u952e\u5b57\u7684\u8986\u76d6\u51fd\u6570\u5e76\u672aoverride\uff0c\u6240\u4ee5\u4ed6\u8fde\u53ef\u884c\u51fd\u6570\u90fd\u7b97\u4e0d\u4e0a\u3002\u81ea\u7136\u65e0\u8bba\u5982\u4f55\u90fd\u4e0d\u53ef\u80fd\u88ab\u8c03\u7528\u3002\u76f8\u53cd\uff0c\u53ef\u80fd\u51fd\u6570\u53ea\u6709Control::Paint();<\/p>\n

\u5982\u679c\u8ba9TextBox::Paint()\u7528override\u4fee\u9970(\u81ea\u7136Control::Paint()\u9700\u8981\u7528virtual\u4fee\u9970),\u90a3\u4e48\u53ef\u80fd\u51fd\u6570\u6709Control::Paint(),TextBox.Paint(),\u5176\u4e2d\u6839\u636e\u52a8\u6001\u51b3\u8bae,\u6700\u4f73\u4e3aTextBox.Paint();<\/p>\n","protected":false},"excerpt":{"rendered":"

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