Dapper官方教程翻译9：Dapper方法之参数类型

2019年02月28日 10:54:45  阅读数：84

 

1.匿名参数（常用）

 

单个查询：

1.  
   string sql = "INSERT INTO Customers (CustomerName) Values (@CustomerName);";
2.  
    
3.  
   using (var connection = new SqlCeConnection("Data Source=SqlCe_W3Schools.sdf"))
4.  
   {
5.  
   var affectedRows = connection.Execute(sql, new {CustomerName = "Mark"});
6.  
    
7.  
   Console.WriteLine(affectedRows);
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   // Only for see the Insert.
10.  
    var customer = connection.Query<Customer>("Select * FROM CUSTOMERS WHERE CustomerName = 'Mark'").ToList();
11.  
     
12.  
    FiddleHelper.WriteTable(customer);
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    }

批量查询：

 

1.  
   string sql = "INSERT INTO Customers (CustomerName) Values (@CustomerName);";
2.  
    
3.  
   using (var connection = new SqlCeConnection("Data Source=SqlCe_W3Schools.sdf"))
4.  
   {
5.  
   var affectedRows = connection.Execute(sql,
6.  
   new[]
7.  
   {
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   new {CustomerName = "John"},
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   new {CustomerName = "Andy"},
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    new {CustomerName = "Allan"}
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    }
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13.  
    Console.WriteLine(affectedRows);
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    )

 

2.动态参数（常用于存储过程）

 

单个操作：

1.  
   var sql = "EXEC Invoice_Insert";
2.  
    
3.  
   using (var connection = My.ConnectionFactory())
4.  
   {
5.  
   connection.Open();
6.  
    
7.  
   DynamicParameters parameter =

   new DynamicParameters();
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9.  
   parameter.Add(

   "@Kind", InvoiceKind.WebInvoice, DbType.Int32, ParameterDirection.Input);
10.  
    parameter.Add(

    "@Code", "Many_Insert_0", DbType.String, ParameterDirection.Input);
11.  
    parameter.Add(

    "@RowCount", dbType: DbType.Int32, direction: ParameterDirection.ReturnValue);
12.  
     
13.  
    connection.Execute(sql,
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    parameter,
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    commandType: CommandType.StoredProcedure);
16.  
     
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    int rowCount = parameter.Get<int>("@RowCount");
18.  
    }

批量操作：

 

1.  
   var sql = "EXEC Invoice_Insert";
2.  
    
3.  
   var parameters = new List<DynamicParameters>();
4.  
    
5.  
   for (var i = 0; i < 3; i++)
6.  
   {
7.  
   var p = new DynamicParameters();
8.  
   p.Add(

   "@Kind", InvoiceKind.WebInvoice, DbType.Int32, ParameterDirection.Input);
9.  
   p.Add(

   "@Code", "Many_Insert_" + (i + 1), DbType.String, ParameterDirection.Input);
10.  
    p.Add(

    "@RowCount", dbType: DbType.Int32, direction: ParameterDirection.ReturnValue);
11.  
     
12.  
    parameters.Add(p);
13.  
    }
14.  
     
15.  
    using (var connection = My.ConnectionFactory())
16.  
    {
17.  
    connection.Open();
18.  
     
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    connection.Execute(sql,
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    parameters,
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    commandType: CommandType.StoredProcedure
22.  
    );
23.  
     
24.  
    var rowCount = parameters.Sum(x => x.Get<int>("@RowCount"));
25.  
    }

 

3.列表参数

 

1.  
   var sql = "SELECT * FROM Invoice WHERE Kind IN @Kind;";
2.  
    
3.  
   using (var connection = My.ConnectionFactory())
4.  
   {
5.  
   connection.Open();
6.  
    
7.  
   var invoices = connection.Query<Invoice>(sql, new {Kind = new[] {InvoiceKind.StoreInvoice, InvoiceKind.WebInvoice}}).ToList();
8.  
   }

 

4.字符串参数

 

1.  
   var sql = "SELECT * FROM Invoice WHERE Code = @Code;";
2.  
    
3.  
   using (var connection = My.ConnectionFactory())
4.  
   {
5.  
   connection.Open();
6.  
    
7.  
   var invoices = connection.Query<Invoice>(sql, new {Code = new DbString {Value = "Invoice_1", IsFixedLength = false, Length = 9, IsAnsi = true}}).ToList();
8.  
    
9.  
   My.Result.Show(invoices);
10.  
    }