Question

我在数据库方法中使用EF Code First，并在asp.net Web应用程序中创建了CRUD操作。现在我想在整个应用程序中过滤一些记录。

我有客户端和产品类

客户端：

public partial class Client
{
    public Client()
    {
        Product = new HashSet<Product>();
    }

    [Key]
    public int ClientID { get; set; }

    [Required]
    [StringLength(5000)]
    public string ClientName { get; set; }

    public string Status { get; set; }

    public virtual ICollection<Product> Product{ get; set; }

产品：

public partial class Product
{
   public Product()
   {

   }
   public int Id { get; set; }
   public string Name { get; set; }
   public string Status { get; set; }
   public virtual Client Client { get; set; }

我想要的是让产品和客户拥有Status =“Active”

我不想在每个页面上手动执行，而是在类级别定义，以便可以在使用Formview的Insert和Edit.aspx自动生成的动态页面上自动完成。请建议可能的方式。

Answer 1

我在我的项目中使用了这个：这允许您添加自己的过滤器方法或只添加FilterByAttribute，指定要过滤的列和要过滤的值。这是通过检查getMethod的存在来实现的，其名称类似于GetTableName，并在每个表上进行检查。您需要在Global.asax文件中使用AdvancedMetaModel替换MetaModel。

希望这会有所帮助。

    public class AdvancedMetaModel : MetaModel
{
    /// <summary>
    /// Creates the table.
    /// </summary>
    /// <param name="provider">The provider.</param>
    /// <returns></returns>
    protected override MetaTable CreateTable(TableProvider provider)
    {
        return new AdvancedMetaTable(this, provider);
    }
}

public class AdvancedMetaTable : MetaTable
{
    private SecureMetaModel SecureModel { get { return (SecureMetaModel)this.Model; } }

    public String GetMethodName { get; set; }

    private MethodInfo CreateQueryMethod { get; set; }

    /// <summary>
    /// Initializes a new instance of the <see cref="AdvancedMetaTable"/> class.
    /// </summary>
    /// <param name="metaModel">The meta model.</param>
    /// <param name="tableProvider">The table provider.</param>
    public AdvancedMetaTable(MetaModel metaModel, TableProvider tableProvider) :
        base(metaModel, tableProvider)
    {
        // set the Get Method Name
        var context = base.CreateContext();
        var getMethodName = DefaultGetMethodName;
        if (context != null && context.HasMethod(DefaultGetMethodName))
        {
            GetMethodName = getMethodName;
            this.CreateQueryMethod = this.DataContextType.GetMethod(GetMethodName);
        }
        else
            GetMethodName = String.Empty;

    }

    internal String DefaultGetMethodName
    {
        get { return String.Format("Get{0}", DataContextPropertyName); }
    }

    public override IQueryable GetQuery(object context)
    {
        var filterByAttribute = this.GetAttribute<FilterByAttribute>();

        if (this.CreateQueryMethod != null)
        {
            if (context == null)
                context = this.CreateContext();
            //this.Provider.GetQuery(context);
            var query = (IQueryable)this.CreateQueryMethod.Invoke(context, null);

            if (this.SortColumn != null)
                return query.GetQueryOrdered((MetaTable)this);
            else
                return query;
        }
        else if (filterByAttribute != null)
        {
            MetaColumn filterByColumn = this.GetColumn(filterByAttribute.ColumnName);
            var query = base.GetQuery(context).GetQueryFilteredByColumn(filterByColumn, filterByAttribute.ValueWhenTrue);
            return query;
        }
        else
        {
            var query = base.GetQuery(context);
            return query;
        }
    }
}
[AttributeUsage(AttributeTargets.Class, AllowMultiple = false)]

public class FilterByAttribute：Attribute { //此属性需要使用＆＃34; AllowMultiple = true＆＃34;参考David Ebbo //实现时，此标识符仅是属性的类型。然而， //旨在使用唯一标识符来标识两个标识符 //相同类型的属性。公共覆盖对象TypeId {get {return this; }}

public String ColumnName { get; set; }

public Object ValueWhenTrue { get; set; }

public FilterByAttribute(String columnName, Object valueWhenTrue)
{
    ColumnName = columnName;
    ValueWhenTrue = valueWhenTrue;
}

Answer 2

她是自定义get方法的示例

public IQueryable GetStations（） { var context = System.Web.HttpContext.Current; var stations = this.Stations.Where（s =＆gt; s.Active）;

if (!context.User.IsInRole("Acctg") && !context.User.IsInRole("Execs"))
{
    var user = MembershipHelpers.GetUser();
    var stationIds = user.Stations.Select(s => s.Id).Distinct().ToList();
    stations = stations.Where(s => stationIds.Contains(s.Id));
}

return stations;

}

asp.net webforms脚手架，EF Code首先来自数据库过滤器记录

2 个答案: