我有以下代码:
@helper RetrievePhotoWithName(int userid)
{
var database = Database.Open("SC");
var name = database.QuerySingle("select FirstName, LastName, ProfilePicture from UserProfile where UserId = @0", userid);
var notifications = database.Query("SELECT COUNT(*) FROM NotificationsTable WHERE UserID = @0 AND MessageWasRead = @1", userid, false);
var DisplayName = "";
if(notifications < 1)
{
DisplayName = name["FirstName"] + " " + name["LastName"];
}
else
{
DisplayName = name["FirstName"] + ", you have " + notifications + " new messages.";
}
<a href="@Href("~/Home")" title="My Account"><img src="@Href("~/Shared/Assets/Images/" + name["ProfilePicture"] + ".png")" id="MiniProfilePicture" /> @DisplayName</a>
database.Close();
}
它应该计算我表中的所有行,并在网页上向用户显示"新通知"消息,或者只显示他们的名字,但它不起作用。
不要编辑这个问题。我重新发布这个问题的原因是因为我之前的问题被更改了,导致回答不准确。
由于SELECT COUNT(*)
返回单个标量值,我认为您想改用database.QueryValue()
:
int notifications = (int)database.QueryValue("SELECT COUNT(*) FROM NotificationsTable WHERE UserID = @0 AND MessageWasRead = @1", userid, false);
http://msdn.microsoft.com/en-us/library/webmatrix.data.database.queryvalue(v=vs.99).aspx
像这样尝试:
@helper RetrievePhotoWithName(int userid)
{
var database = Database.Open("SC");
var name = database.QuerySingle("select FirstName, LastName, ProfilePicture from UserProfile where UserId = @0", userid);
var notifications = database.Query("SELECT convert(int,COUNT(*)) as 'counter' FROM NotificationsTable WHERE UserID = @0 AND MessageWasRead = @1", userid, false);
var DisplayName = "";
if(notifications["counter"] < 1)
{
DisplayName = name["FirstName"] + " " + name["LastName"];
}
else
{
DisplayName = name["FirstName"] + ", you have " + notifications["counter"] + " new messages.";
}
<a href="@Href("~/Home")" title="My Account"><img src="@Href("~/Shared/Assets/Images/" + name["ProfilePicture"] + ".png")" id="MiniProfilePicture" /> @DisplayName</a>
database.Close();
}