Question

您好我正在学校为学生构建一个帮助应用程序，使用数据库和信号器来实时更新列表。

connection.Open();
            using (var command = new SqlCommand(@"SELECT [Id], [Name] FROM [dbo].[HelpLists]", connection))
    {
    command.Notification = null;

    var dependency = new SqlDependency(command);
    dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);

    if (connection.State == ConnectionState.Closed)
        connection.Open();

    var reader = command.ExecuteReader();
    while (reader.Read())
    {
        messages.Add(item: new Messages { Number = (int)reader["Id"], Message = (string)reader["Name"] });
    }

}

我想要的代码部分是While loop

让我说我的select语句有3行。然后我想将command传递给for / foreach loop有点像：

for (int i = 0; i < reader.FieldCount; i++)
    {
         messages.Add(item: new Messages { Number = i + 1, Message = (string)reader["Name"] });
    }

原因是我需要从1开始的数字，并且对于select语句中的每一行增加1

Answer 1

您可以尝试此代码。

connection.Open();
            using (var command = new SqlCommand(@"SELECT [Id], [Name] FROM [dbo].[HelpLists]", connection))
    {
    command.Notification = null;

    var dependency = new SqlDependency(command);
    dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);

    if (connection.State == ConnectionState.Closed)
        connection.Open();

    var reader = command.ExecuteReader();
//my change is here
List<reader > readers = new List<reader>();
for(reader rs:readers )
{


System.out.println(rs.id);
System.out.println(rs.name);
}
}

在for / foreach循环中运行Sql select语句

1 个答案: