RE: What is the difference between adding reference in...
Adding reference in solution explorer is used to add the DLL for that project for reference only. If you want to utilize that DLL methods/functions in our aspx.cs/.cs file etc you must write using that nameclass library name in file.
RE: What is the difference between adding reference in solution Explorer and adding references by USING
Adding referece in solution exploere comes with adding of like assemlie to the application. Means of adding private assemblies to the application. Where as adding refernce using denotes that these DDL's are to be laoded into the memory while running this particular page and this methods from this assembly are being utilised in this page.
RE: What is the difference between adding reference in solution Explorer and adding references by USING
Adding reference in solution explorer is used to add the DLL for that project for reference only. If you want to utilize that DLL methods/functions in our aspx.cs/.cs file etc you must write using that nameclass library name in file.