小编Pas*_*mey的帖子

我正在尝试针对Entity框架(或其他Linq提供程序)创建动态查询.

让我用一些示例代码解释我的问题.

如果我硬编码表达式:

var id = 12345;

Expression<Func<ItemSearch, bool>> myLambda = (s) => s.Id == id;

var finalQuery = context.ItemSearch.Where(myLambda);
this.Log((finalQuery as ObjectQuery).ToTraceString());

生成的SQL如下所示:

SELECT ...
FROM ViewItemSearch "Extent1"
WHERE "Extent1".ID = :p__linq__0

用一个很好的:p__linq__0dbParameter.

如果我创建一个表达式:

var id = 12345;
ParameterExpression param = Expression.Parameter(typeof(ItemSearch), "s");
Expression prop = Expression.Property(param, "Id");
Expression val = Expression.Constant(id);
Expression searchExpr = Expression.Equal(prop, val);

Expression<Func<ItemSearch, bool>> myLambda =  
    Expression.Lambda<Func<ItemSearch, bool>>(searchExpr , param);

var finalQuery = context.ItemSearch.Where(myLambda);
this.Log((finalQuery as ObjectQuery).ToTraceString());

生成的SQL如下所示:

SELECT ...
FROM ViewItemSearch …

在传统的Asp.NET webforms应用程序中,我尝试注入一些IOC.

我不会详细介绍,但对于这一点,我认为ServiceLocator是一个很好的工具.我知道服务定位器是反模式的; o)

根据文档https://github.com/autofac/Autofac/wiki/Common-Service-Locator,ServiceLocator配置如下所示:

var container = builder.Build();
var csl = new AutofacServiceLocator(container);
ServiceLocator.SetLocatorProvider(() => csl);

问题是LoacatorProvider是使用根容器设置的.因此,终身管理不活跃.

我正在考虑解决这个问题的方法

因为ServiceLocator.SetLocatorProvider将一个委托作为参数,并且因为在每次调用时调用此委托,ServiceLocator.Current为什么不为每个请求提供一个AutofacServiceLocator实例.

public class Global : HttpApplication, IContainerProviderAccessor
{
    // Provider that holds the application container.
    static IContainerProvider _containerProvider;

    void Application_Start(object sender, EventArgs e)
    {
        // Code that runs on application startup
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);

        _containerProvider = new ContainerProvider(AutoFacBootstrapper.CreateContainer());

        ServiceLocator.SetLocatorProvider(() =>
        {
            AutofacServiceLocator asl = HttpContext.Current.Items["AutofacServiceLocator"] as AutofacServiceLocator;
            if (asl == null)
            {
                var cpa = (IContainerProviderAccessor)HttpContext.Current.ApplicationInstance; …

我有ServiceStack.CacheAccess.Memcached的问题.MemcachedClientCache.该Increment方法无法按预期工作.

对于测试,我使用的是常规控制台应用程序和ICacheClient界面.

根据方法文档:

必须先将项目插入缓存,然后才能更改该项目.
该项必须作为a插入System.String.
该操作仅适用于System.UInt32values,因此-1始终表示未找到该项.

所以我们走了:

ICacheClient client = new MemcachedClientCache();
string key = "test";
bool result = client.Remove(key);
Console.WriteLine("{0} removed: {1}", key, result);

//The item must be inserted as a System.String.   
result = client.Add(key, "1");
Console.WriteLine("added {0}", result);


long v = client.Increment(key, 1);
Console.WriteLine("first increment : {0}", v);

string o = client.Get<string>(key);
Console.WriteLine("first read: {0}", o);

v = client.Increment(key, 1);
Console.WriteLine("second increment: {0}", v);

o = client.Get<string>(key);
Console.WriteLine("second …