@Jimi是对的，我无意中创建了一个.NET核心项目，因此一些没有引用的地方把整个项目搞得一团糟。
'System.Array' does not contain a definition for 'Select' and no extension method 'Select' 'System.Windows.Forms.Button' does not contain a definition 'System.Xml.XmlException' occurred in System.Xml.dll Visual C#? 'Transaction failed. The server response was: 5.7.1 Relay access denied in ...
Forms.Button' does not contain a definition 'System.Xml.XmlException' occurred in System.Xml.dll Visual C#? 'Transaction failed. The server response was: 5.7.1 Relay access denied in asp.net' 'Windows' does not exist in the namespace 'System'... "_" underscore keyword in asynchronous "...
32 bit Application calling 32 bit DLL "An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)" 4 digit precision- String format 405 method not allowed(postman) 500 Internal server Error while calling a webservice through Httprequest 64 bit app ...
Forms.Button' does not contain a definition 'System.Xml.XmlException' occurred in System.Xml.dll Visual C#? 'Transaction failed. The server response was: 5.7.1 Relay access denied in asp.net' 'Windows' does not exist in the namespace 'System'... "_" underscore keyword in asynchronous "...