Simple login form with LINQ to Entities and C# 4.0

Question

Hi I need help to make simple login C# 4.0 winform using LINQ to entities Thank you.

Bikesh Srivastava · Answer

Hi Please follow this link. https://msdn.microsoft.com/en-us/data/jj682076.aspx

Samio · Answer

Hi chirag I failed to run your code in a Windows Form in spite of creating one Entity data Model named testchiragentities based on a database named testchirag with one table named Login. also what I need is to log in an existing user and not to register a new one. So I need a form with 2 text boxes 2 labels and 1 Button which sould run the code uppon click Event. The code as used is the next: //User name came from UserInput string UserName = chirag; bool IsUserAlreadyExist = false; { //Entity FrameWork Object using (testchiragEntities repository = new testchiragEntities()) //Check whether User name already exist in database IsUserAlreadyExist = repository.Login.Where(x => x.LoginUserName == UserName).Count() > 0; } //true : false; //if user already exist then show un successfull message if (IsUserAlreadyExist) MessageBox.Show(Username already exist! please use another username); else //if user no exist then show welcome message MessageBox.Show(Welcome to site!); } Thank you for your help

chirag pandya · Answer

Hi I have given test example. testchiragEntities is my ADO.NET Entity Data ModelSo for your scenario you have to make your own. Following are steps to create it 1) You have create one solution and right click on solution. Add new Item select data Template from left panel then create ADO.NET Entity Data Model (.edmx) file. 2) Go throgh a step and attach with your database i have Login table in my database. 3) Then after creating your EDMX file now you can access you table with strongly type in coding(In my case i have test database name=testchirag and one table name Login) one more thing and if you are using window base application then put code in static void Main( string [] args) {}

Samio · Answer

@Chirag I have got: Error 1 A namespace cannot directly contain members such as fields or methods for: string UserName = chirag;bool IsUserAlreadyExist = false; and got: Error 3 Expected class delegate enum interface or struct for: using ( testchiragEntities repository = new testchiragEntities ())

chirag pandya · Answer

//User name came from UserInput string UserName = chirag ; bool IsUserAlreadyExist = false ; { //Entity FrameWork Object using ( testchiragEntities repository = new testchiragEntities ()) //Check whether User name already exist in database IsUserAlreadyExist = repository.Logins.Where(x => x.LoginUserName == UserName).Count() > 0 ? } true : false ; //if user already exist then show un successfull message if (IsUserAlreadyExist) MessageBox .Show( Username already exist! please use another username ); else //if user no exist then show welcome message MessageBox .Show( Welcome to site! );