小编k80*_*0sg的帖子

我将我的ddl绑定到我的数据库,如下所示,但是如何在绑定值的顶部添加默认文本,使其显示为:

Select Color ---> default text
Red ---> database value
Blue ---> database value
Green ---> database value   

码:

    DropDownList ddlSize = (DropDownList)FormView_Product.Row.Cells[0].FindControl("ddlSize");
    CommerceEntities db = new CommerceEntities();

    ddlColor.DataSource = from p in db.ProductTypes
                                      where p.ProductID == pID
                                      orderby p.Color 
                                      select new { p.Color };
    ddlColor.DataTextField = "Color";

谢谢!

我对CSS选择器感到困惑,我知道如果它们共享相似的属性,我们可以使用逗号对多个css选择器进行分组,但是如果没有逗号的多个css选择器怎么样,例如:

.ui-datepicker-rtl { direction: rtl; }
.ui-datepicker-rtl .ui-datepicker-prev { right: 2px; left: auto; }
.ui-datepicker-rtl .ui-datepicker-next { left: 2px; right: auto; }

刚刚间歇性地遇到了这个错误:

Google has disabled use of the Maps API for this application. See the Terms of Service for more information: http://www.google.com/intl/en-US_US/help/terms_maps.html.

不知何故,当我刷新页面时,地图又回来了.我认为如果它是违规行为,它将永久撤销密钥,并且不再允许使用此密钥加载地图.此外,错误总是发生在页面加载.如果它已经成功加载,我还没有遇到错误.我简要地阅读了这些条款但却找不到任何可疑的东西.任何人都可以建议如何解决这个错误？我应该检查一些js错误或地图条款吗？谢谢.

这是地图脚本的样子:

<script src="http://maps.google.com/maps/api/js?v=3&sensor=false&libraries=places&key=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" type="text/javascript"> </script>

我在asp.net中遇到了几种编写业务逻辑的方法,但我想知道下面的两个例子,使用struct来存储类变量有什么好处:

namespace Shopping
{
   public struct ShoppingCart
   {
       public string Color;
       public int ProductId;
   }

   public partial class MyShoppingCart 
   {

       public decimal GetTotal(string cartID)
       {
       }

       // Some other methods ...
   }
}

namespace Shopping
{
   public partial class MyShoppingCart 
   {
       public string Color{ get; set; }
       public int ProductId{ get; set; }

       public decimal GetTotal(string cartID)
       {
       }

       // Some other methods ...
   }
}

嗨,我正在准备面试代码测试,我偶然发现了这个问题.我想尝试在C#中,下面是我尴尬的回答,我甚至不知道这是否是正确的,但主要是我想不会,能不能有人请您为我提供答案,这样,当我返工的解决方案,我至少可以有验证输出的答案.谢谢.

样本数据:

int[] arr = {5, 1, -7, 3, 7};

码:

int[] LargestsubarrayMaxSum(int[] arr)
{
    int temp = 0;
    int[] resultArr = new int[arr.Length];

    for (int i = 0; i < arr.Length - 1; i++)
    {
        if (i != 0)
        {
            foreach (int item in resultArr)
            {
                temp += item;
            }

            if (temp + arr[i + 1] > 0)
            {
                resultArr[i + 1] = temp + arr[i + 1];
            }
        }
        else
        {
            if ((arr[i] + arr[i + 1]) >= …

我有一个数据库字段名称调用Code,我试图使用如下所示的变量名称选择它:

Declare @var1 = [Code]

(SELECT @var1
 FROM [VoucherType]
 WHERE [DeletedBy] IS NULL
 AND [AutoID] = 1)

显然,SQL将解释@var1为字符串而不是我的数据库字段,如何以这种方式@var1将其识别为字段名称[Code]而不是字符串,可能没有任何select或if语句.

有什么区别:

Dim intVal as integer
intVal = 0

和

intVal = nothing

我从MSDN上读到没有任何东西将值设置为0:

来自MSDN:

Public Structure testStruct
    Public name As String
    Public number As Short
End Structure
Dim ts As testStruct, i As Integer, b As Boolean
ts = Nothing 
' The preceding statement sets ts.name to "" and ts.number to 0.
i = Nothing 
b = Nothing 
' The preceding statements set i to 0 and b to False. 

我试图加入一串数据库值,但在此声明中:

SET @sql = ('select' + @var1 + '+' + convert(varchar,@var2) + 
            'from [VoucherType] where [DeletedBy] is null and [AutoID] = 1')

我收到一个错误说

数据类型nvarchar和bit在add运算符中不兼容.

@var2这是[IsBirthdayVoucher]我的数据库是一个bit类型,但我已经申请convert(varchar, @var2)就可以了.请善意地告诉我做错了什么.谢谢.

存储过程:

declare @Str as varchar(max) 
declare @var1 as varchar(30)=null
declare @var2 as varchar(30)=null
declare @var3 as varchar(30)=null
declare @var4 as varchar(30)=null
declare @var5 as varchar(30)=null

declare @sql as varchar(355)

set @Str = '[Code][IsBirthdayVoucher][IsReusable]VouT' 

    Set @var1=  (select LEFT(@Str, CHARINDEX(']', @Str)))  
        set @Str = SUBSTRING(@Str, CHARINDEX(']', @Str) + 1, …

我对数据库设计相当新,对于多对多的关系,创建复合键的差异和含义是什么,以及对于例如

Country 表

CountryID
CountryName

Language 表

LanguageID
LangugageName

多对多表 - 使用复合:

CountryID  Pkey
LanguageID Pkey

要么

使用唯一ID:

AutoID Pkey
CountryID 
LanguageID 

我试图执行以下动态查询,但我收到一个错误:无效的列名称'猫'

 DECLARE @SQLDelQuery AS NVARCHAR(1200)   
 DECLARE @MemberNames varchar(50)

 SET @MemberNames = 'cat'

      SET @SQLDelQuery = 'SELECT [Email] FROM [aspnet_Membership] am
      INNER JOIN [aspnet_Users] u
      ON (am.UserId = u.UserId)
      INNER JOIN [Member] m
      ON (am.UserId = m.UserId)
      WHERE u.UserName IN (' + @MemberNames + ')

  EXECUTE(@SQLDelQuery)

如果我将其更改为正常查询我很好:

SELECT [Email] FROM [aspnet_Membership] am
  INNER JOIN [aspnet_Users] u
  ON (am.UserId = u.UserId)
  INNER JOIN [Member] m
  ON (am.UserId = m.UserId)
  WHERE u.UserName IN ('cat')

任何人都可以指出我的错误？谢谢.