设置EntityFramework中decimal类型数据精度

EF中默认的decimal数据精度为两位数，当我们数据库设置的精度大于2时，EF将只会保留到2为精度。

e.g.  2.1999将会被保存为2.20

网上找到常见的方法为重写DbContext的OnModelCreating方法：

protected override void OnModelCreating(DbModelBuilder modelBuilder)

{

　　modelBuilder.Entity<Product>().Property(x => x.Price).HasPrecision(18, 4);

}

但如果数据表多或者Decimal类型字段多的话，用OnModelCreating的方法将会变得相当冗余，而且不便管理。

我推荐使用Attribute属性标签进行设置，在Entity Model class中decimal的字段上方直接添加自定义拓展的属性标签即可。

e.g.

其中 [DecimalPrecision(18, 4)]即是我们自定义的精度Attribute

具体实现代码如下：

/// <summary>

    /// <para>自定义Decimal类型的精度属性</para>

    /// </summary>

    [AttributeUsage(AttributeTargets.Property, Inherited = false, AllowMultiple = false)]

    public sealed class DecimalPrecisionAttribute : Attribute

    {

        #region Field

        private byte _precision = ;

        public byte _scale = ;

        #endregion

        #region Construct

        /// <summary>

        /// <para>自定义Decimal类型的精确度属性</para>

        /// </summary>

        /// <param name="precision">precision

        /// <para>精度（默认18）</para></param>

        /// <param name="scale">scale

        /// <para>小数位数（默认4）</para></param>

        public DecimalPrecisionAttribute(byte precision = , byte scale = )

        {

            Precision = precision;

            Scale = scale;

        }

        #endregion

        #region Property

        /// <summary>

        /// 精确度（默认18）

        /// </summary>

        public byte Precision

        {

            get { return this._precision; }

            set { this._precision = value; }

        }

        /// <summary>

        /// 保留位数（默认4）

        /// </summary>

        public byte Scale

        {

            get { return this._scale; }

            set { this._scale = value; }

        }

        #endregion

    }

    /// <summary>

    /// 用于modelBuilder全局设置自定义精度属性

    /// </summary>

    public class DecimalPrecisionAttributeConvention

        : PrimitivePropertyAttributeConfigurationConvention<DecimalPrecisionAttribute>

    {

        public override void Apply(ConventionPrimitivePropertyConfiguration configuration, DecimalPrecisionAttribute attribute)

        {

            if (attribute.Precision <  || attribute.Precision > )

            {

                throw new InvalidOperationException("Precision must be between 1 and 38.");

            }

            if (attribute.Scale > attribute.Precision)

            {

                throw new InvalidOperationException("Scale must be between 0 and the Precision value.");

            }

            configuration.HasPrecision(attribute.Precision, attribute.Scale);

        }

    }

再在DbContext重写OnModelCreating，添加自定义的DecimalPrecisionAttributeConvention即可以方便地任意添加需要精度控制的字段。

public class Project_DbContext : DbContext

    {

        public Project_DbContext() : base("DefaultConnection") { }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)

        {

            modelBuilder.Conventions.Add(new DecimalPrecisionAttributeConvention());

            base.OnModelCreating(modelBuilder);

        }

    }

巴特西

设置EntityFramework中decimal类型数据精度

最新文章

热门文章