实体框架:获取元数据IProperty的数据类型 [英] Entity Framework: Get the DataType of Metadata IProperty

问题描述

如何在Entity Framework Core中找到Metadata.IProperty的数据类型?

How do I find the DataType of Metadata.IProperty in Entity Framework Core?

var tableType = _dbContext.Model.GetEntityTypes().First(c => c.GetTableName() == tableName);
foreach (var property in tableType.GetProperties())
{
     var test = property.PropertyInfo.PropertyType.Name;

使用 property.PropertyInfo.PropertyType.Name 有时会起作用，但是对于可为空的对象，它会打印为null.我正在寻找一种获取数据类型的干净方法.

Using property.PropertyInfo.PropertyType.Name, sometimes works, however for nullable objects it prints null. I am looking for a clean way to get data type.

推荐答案

IProperty 的 Type 由 ClrType 属性表示.它可以正确处理两个实际属性(具有 PropertyInfo )和字段(EF Core 5.0+

The Type of the IProperty is represented by ClrType property. It handles correctly both real properties (having PropertyInfo), fields (EF Core 5.0+ allow mapping fields as properties), and also shadow properties which have no assocaited PropertyInfo or FieldInfo at all.

var tableType = _dbContext.Model.GetEntityTypes().First(c => c.GetTableName() == tableName);
foreach (var property in tableType.GetProperties())
{
    Type type = property.ClrType;
}

现在谈论该 Type 的字符串表示形式，它是任意的(类似于任何格式)，并取决于您的需求.例如，出于调试显示的目的，EF Core在内部使用

Now speaking about string representation of that Type, it is arbitrary (similar any formatting) and depends on your needs. For instance, for debug display purposes EF Core internally uses the ShortDisplayName method. You can eventually use it, but note that it uses C# built-in types (e.g. int instead of Int32) and formats nullable type as "Nullable<{TypeName}>" e.g.

需要

using Microsoft.EntityFrameworkCore.Infrastructure;

然后

var tableType = _dbContext.Model.GetEntityTypes().First(c => c.GetTableName() == tableName);
foreach (var property in tableType.GetProperties())
{
    var type = property.ClrType;
    var typeName = type.ShortDisplayName();
}

同样，将 Type 转换为 string 的方式有所不同，具体取决于该字符串的用途.因此，请尽可能使用 Type 而不是 string . GetColumnType 是不同的-它返回字符串，因为没有类似于 Type 的类来表示数据库提供程序类型.

Again, converting Type to string differs, and depends on what this string will be used for. So use Type instead of string where possible. GetColumnType is different - it returns string because there is no class similar to Type to represent the database provider types.

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