添加项目文件。

Entities/DTO/ClassDto.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Entities.DTO
+{
+	public class ClassDto
+	{
+		public byte Class { get; set; }
+
+		[StringLength(50, ErrorMessage = "班级名称不能超过 50 个字符。")]
+		public string Name { get; set; }
+
+		[Required(ErrorMessage = "年级是必填项。")]
+		[Range(1, 12, ErrorMessage = "年级编号必须在 1 到 12 之间。")] 
+		public byte Grade { get; set; }
+
+		public string Description { get; set; } = "HELLO WORLD";
+
+
+		public int? HeadTeacherId { get; set; }
+	}
+}