WinForm using LINQ to SQL class to implement database add, delete, change, check February 18, 2016

In C #, if you are using a SQL Server database, you can use the LINQ to SQL class to make operations on the database easier because of the same Microsoft-owned software.

One, add a LINQ to SQL class:

Second, in the data connection in the Resource Manager, connect the database:

Third, the table to be operated, dragged into the DATACLASSES1.DBML operator panel, so that the table properties are encapsulated

Four, create a FRUITDA class, in the inside write the database to add, delete, change, check the method, the code is as follows:

  Public classFRUITDA {PrivateDataclasses1datacontext Context;//create a LINQ to SQL Class object context, data Model        PublicFruitda () {Context=NewDataclasses1datacontext ();//constructor to instantiate the context inside       }        Public voidInsert (Fruit data)//Add Method{Context.Fruit.InsertOnSubmit (data);//adding data to the fruit tableContext.submitchanges ();//have changed, commit to database       }        Public voidUpdate (Fruit data)//Modify Method       {            //query First, then modifyFruit sdata = Context.Fruit.Where (r = R.ids = =data. IDS).           First (); //The equal sign greater than sign is an LAMDA expression, and the equals sign is equal to the in list of the list generic collection//R can be arbitrarily named, representing a row of data, the equivalent of fruit data in Data,foreach each row is a row of data, a row of data is//If they are equal, if they are not equal, go to the next bar.//after the filter is finished, take the data from the first one, and return an object of type fruit.           if(Sdata! =NULL)//Judging if the data is not empty, follow the sdata data to modify the data{sdata. Name=data.               Name; Sdata. Price=data.               Price; Sdata. Numbers=data.               Numbers; Sdata. Source=data.               Source; Sdata. Stack=data.               Stack; Sdata. Image=data.           Image; } context.submitchanges ();//Modify commit to Database       }        Public voidDelete (Fruit data)//Delete Method{Context.Fruit.DeleteOnSubmit (data);       Context.submitchanges (); }        PublicList<fruit> Select ()//Query method that returns a generic collection of type fruit       {           returnContext.Fruit.ToList ();//Convert the result to a generic collection using the ToList function       }        PublicList<fruit> Selectbyname (stringName//Fuzzy Query       {           returnContext.Fruit.Where (r=>r.name.contains (Name)).           ToList (); //See if the filtered line has a name like name, with a contains package that does not contain the defined lower case, and then converts to a generic collection to return       }        Public BOOLCheckfruit (stringNamedecimalPrice//to verify the style of the user name password       {           returnContext.Fruit.Where (r = r.name = = Name && R.price = = Price). Count () >0; //filter multiple conditions at the same time to satisfy the &&, and the number of bars that satisfy the condition data with Count//if greater than 0 returns true, less than or equal to zero returns false       }        PublicFruitSelect(stringIDs//querying a single piece of data       {           returnContext.Fruit.Single (r = R.ids = =IDs); //If the query is a primary key, you can use single//not a primary key, use where to filter       }    }

The test code is as follows:

Private void Form1_Load (object  sender, EventArgs e)        {            Listnew  FRUITDA (). Select ();             = list;        }

WinForm using LINQ to SQL class to implement database add, delete, change, check February 18, 2016