小编use*_*986的帖子

编译得很好,但执行失败,标题中出现错误.

ArtistService.cs

public class ArtistService : IArtistService
{
    public List<Artist>  ArtistDetail()  
    {
        using (ArtistDataContext db = new ArtistDataContext())
        {
            return (from artist in db.Artists

                select new Artist()
                {
                    Id = artist.Id,
                    Artist_name = Artist.Artist_name
                }).ToList();     <=== error happened here
        }
    }
}

代码背后

private List<ArtistServiceReference.Artist> ArtistDetail()
{
    ArtistServiceReference.ArtistServiceClient client = new 
    ArtistServiceReference.ArtistServiceClient();

    ArtistServiceReference.Artist[] artists = client.ArtistDetail();

    return artists.ToList();

我想将Artist List移动​​到DropdownList.

错误发生在最后的ArtistService.cs中{.ToList(); 有关如何解决此问题的任何解释？谢谢

我将我的代码基于此示例,此示例工作正常.

示例代码MyService.cs

public class MyService : IMyService
{
    public List<Task> GetTasks()
    {
        using (TasksDataContext db = new TasksDataContext()) …

我从标签转换此车钥匙密码时出现问题.这是我收到的错误

无法将类型为"System.Web.UI.WebControls.HiddenField"的对象强制转换为"System.Web.UI.WebControls.Label".

你有什么建议可以避免这个错误吗？

谢谢

Label myCarId = (Label)item.FindControl("carId");
iCarId = Convert.ToInt32(myCarId);
Session["carId"] = iCarId;

我有这个sql查询应该返回0的计数,但我想这是很糟糕的构建.

这是我执行的SQL代码

string cmdText = @"SELECT count(*) 
                   From Apointement 
                   WHERE emailClient=@emailClient AND 
                       trialdate=@trialdate AND 
                       TrailHour=trialhour";

SqlCommand cmd = new SqlCommand(cmdText, con);

cmd.Parameters.AddWithValue("@emailClient", Convert.ToString(Session["email"]));
cmd.Parameters.AddWithValue("@trialdate",dDateApt);
cmd.Parameters.AddWithValue("@trialhour", sHourApt);

if (con.State == ConnectionState.Closed)
{
    con.Open();
}

int nbrofRec = (int) cmd.ExecuteScalar();
if (nbrofRec >= 1)

此查询返回1作为计数.

查询中的数据如下:

email     = s.brown@rv.com  
trialdate = 1/27/2014 12:00:00AM  
trialhour = 10:00

数据库中的日期

email     = s.brown@rv.com  
trialdate = 1/27/2014 
trialhour = 12:00       <=== notice the only appointment is at 12:00 not at 10:00

我找不出哪个元素是错的.

我有一个textBox字段,MaxLength设置为255.我可以在文本框中输入超过255个字符.我原以为有255个字符的限制.有没有办法控制它？我需要使用背后的代码吗？我们可以使用RequiredFieldValidator来控制它吗？

这是.aspx中的代码

 <asp:TextBox ID="txtCommentaire" runat="server" Width="600px" MaxLength="255" TextMode="MultiLine" 
 Height="90px" style="overflow:hidden" ></asp:TextBox>

我有DateTime.ParseExtract的问题.错误是String was not recognized as a valid DateTime.

sqlserver 2012中的trialDate定义为folllow type = date,它以MM/dd/yyyy格式显示.我想这是sqlserver的默认设置.我不知道如何以及在何处将其更改为dd/MM/yyyy或dd-MM-yyyy.

当我在listview中显示日期时,我做了这个(戴上面具):'

这是C#代码隐藏

    string sTrialDate = "";
    foreach (ListViewDataItem item in ListView1.Items)
    {
       CheckBox MyCheckBox = (CheckBox)item.FindControl("MyCheckBox");
       if (MyCheckBox.Checked) 

       {
           Label myTrialDate = (Label)item.FindControl("trialDatelbl");
           sTrialDate = myTrialDate.Text;
       }
    }

问题是DATETIME.ParseExtract,这是我到目前为止所尝试的:

   DateTime dt = DateTime.ParseExact("sTrialDate", "MM/dd/yyyy",   
           System.Globalization.CultureInfo.InvariantCulture);    <=== not working

   DateTime dt = DateTime.ParseExact("sTrialDate", "dd/MM/yyyy",   
           System.Globalization.CultureInfo.InvariantCulture);    <=== not working

   DateTime dt = DateTime.ParseExact("sTrialDate", "dd/MM/yyyy ",   
           System.Globalization.CultureInfo.InvariantCulture);    <=== not working

   DateTime dt = DateTime.ParseExact(Request.QueryString["sTrialDate"], "dd/MM/yyyy", null);              
                                                                                <==not working