原文: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. 2.19990将会被保存为2.20
1.解决方案一是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, 5); }
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。
2.解决方案二是我推荐使用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。
调用:
其中 [DecimalPrecision(18, 5)]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 class DecimalPrecisionAttribute : Attribute { #region Field private byte _precision = 18; public byte _scale = 5; #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5）</para></param> public DecimalPrecisionAttribute(byte precision = 18, byte scale = 5) { 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5） /// </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< 1 || attribute.Precision> 38) { 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); } }
