将动态类与 TableEntityAdapter 一起用于 Azure 表存储

Posted 2023-03-28

【中文标题】将动态类与 TableEntityAdapter 一起用于 Azure 表存储

【英文标题】：Using dynamic class with TableEntityAdapter for Azure Table Storage

【发布时间】：2021-09-13 06:52:42

【问题描述】：

我有以下代码行：

var entity = new TableEntityAdapter<object>(obj, partitionKey, id);

对象obj 包含属性，当我保存到表存储时，这些属性不会保存。我明白为什么，因为它们没有在 object 类中定义。

如何定义 TableEntityAdapter 在运行时使用的类？

更新

是的，我使用 ElasticTableEntity 解决了这个问题，如下所述 - 但是，我还发现现在有一个内置的 DynamicTableEntity，这是默认的表格结果。它具有相同的目的。

【参考方案1】：

更新：

Microsoft.Azure.Cosmos.Table 的最新版本有一个内置类 ElasticTableEntity，它正好用于此目的。

旧解决方案：

我使用这个 ElasticTableEntity 解决了它

http://pascallaurin42.blogspot.com/2013/03/using-azure-table-storage-with-dynamic.html

public class ElasticTableEntity : DynamicObject, ITableEntity,
    ICustomMemberProvider // For LinqPad's Dump

    public ElasticTableEntity()
    
        this.Properties = new Dictionary<string, EntityProperty>();
    
    
    public IDictionary<string, EntityProperty> Properties  get; private set; 
 
    public object this[string key] 
     
        get
        
            if (!this.Properties.ContainsKey(key))
                this.Properties.Add(key, this.GetEntityProperty(key, null));
 
            return this.Properties[key];
        
        set
        
            var property = this.GetEntityProperty(key, value);
            
            if (this.Properties.ContainsKey(key))
                this.Properties[key] = property;
            else
                this.Properties.Add(key, property);
        
    
    
    #region DynamicObject overrides
 
    public override bool TryGetMember(GetMemberBinder binder, out object result)
    
        result = this[binder.Name];
        return true;
    
 
    public override bool TrySetMember(SetMemberBinder binder, object value)
    
        this[binder.Name] = value;
        return true;
    
    
    #endregion
    
    #region ITableEntity implementation
    
    public string PartitionKey  get; set; 
 
    public string RowKey  get; set; 
 
    public DateTimeOffset Timestamp  get; set; 
 
    public string ETag  get; set; 
    
    public void ReadEntity(IDictionary<string, EntityProperty> properties, OperationContext operationContext)
    
        this.Properties = properties;
    
 
    public IDictionary<string, EntityProperty> WriteEntity(OperationContext operationContext)
    
        return this.Properties;
    
    
    #endregion
    
    #region ICustomMemberProvider implementation for LinqPad's Dump
    
    public IEnumerable<string> GetNames()
    
        return new[]  "PartitionKey", "RowKey", "Timestamp", "ETag" 
            .Union(this.Properties.Keys);
    
    
    public IEnumerable<Type> GetTypes()
    
        return new[]  typeof(string), typeof(string), typeof(DateTimeOffset), typeof(string) 
            .Union(this.Properties.Values.Select(x => this.GetType(x.PropertyType)));
    
    
    public IEnumerable<object> GetValues()
    
        return new object[]  this.PartitionKey, this.RowKey, this.Timestamp, this.ETag 
            .Union(this.Properties.Values.Select(x => this.GetValue(x)));
    
    
    #endregion
    
    private EntityProperty GetEntityProperty(string key, object value)
    
        if (value == null) return new EntityProperty((string)null);
        if (value.GetType() == typeof(byte[])) return new EntityProperty((byte[])value);
        if (value.GetType() == typeof(bool)) return new EntityProperty((bool)value);
        if (value.GetType() == typeof(DateTimeOffset)) return new EntityProperty((DateTimeOffset)value);
        if (value.GetType() == typeof(DateTime)) return new EntityProperty((DateTime)value);
        if (value.GetType() == typeof(double)) return new EntityProperty((double)value);
        if (value.GetType() == typeof(Guid)) return new EntityProperty((Guid)value);
        if (value.GetType() == typeof(int)) return new EntityProperty((int)value);
        if (value.GetType() == typeof(long)) return new EntityProperty((long)value);
        if (value.GetType() == typeof(string)) return new EntityProperty((string)value);
        throw new Exception("not supported " + value.GetType() + " for " + key);
    
    
    private Type GetType(EdmType edmType)
    
        switch (edmType)
        
            case EdmType.Binary : return typeof(byte[]);
            case EdmType.Boolean : return typeof(bool);
            case EdmType.DateTime : return typeof(DateTime);
            case EdmType.Double : return typeof(double);
            case EdmType.Guid : return typeof(Guid);
            case EdmType.Int32 : return typeof(int);
            case EdmType.Int64 : return typeof(long);
            case EdmType.String : return typeof(string);
            default: throw new Exception("not supported " + edmType);
        
    
 
    private object GetValue(EntityProperty property)
    
        switch (property.PropertyType)
        
            case EdmType.Binary : return property.BinaryValue;
            case EdmType.Boolean : return property.BooleanValue;
            case EdmType.DateTime : return property.DateTimeOffsetValue;
            case EdmType.Double : return property.DoubleValue;
            case EdmType.Guid : return property.GuidValue;
            case EdmType.Int32 : return property.Int32Value;
            case EdmType.Int64 : return property.Int64Value;
            case EdmType.String : return property.StringValue;
            default: throw new Exception("not supported " + property.PropertyType);