MVC中数据的内部校验

针对MVC中实例类型的修饰，我们可以采用DataAnnotations类来完成，该类所处的命名空间是System.ComponentModel.DataAnnotations;

一、通过开类型，能够修改Model类型的属性，如下代码所示：

public class Employee
    {
        [Key]
        public int EmployeeId { get; set; }

        [Required(ErrorMessage = "Enter First Name"), StringLength(50)]
        public string FirstName { get; set; }

        [StringLength(50,ErrorMessage="Last Name length should be greater than 50")]
        public string LastName { get; set; }

        public int Salary { get; set; }
    }

备注：

1、[key]主键唯一，Required必填，ErrorMessage错误提示内容，StringLength表述字段长度。

Form表单代码：

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>CreateEmployee</title>
</head>
<body>
    <div>
        <form action="/Employee/SaveEmployee" method="post">
           <table>
            <tr>
                <td>First Name:</td>
                <td><input type="text" id="TxtFName" name="FirstName" value="" /></td>
                <td>@Html.ValidationMessage("FirstName")</td>
            </tr>
            <tr>
                <td>Last Name:</td>
                <td><input type="text" id="TxtLName" name="LastName" value="" /></td>
                <td>@Html.ValidationMessage("LastName")</td>
            </tr>
            <tr>
                <td>Salary:</td>
                <td><input type="text" id="TxtSalary" name="Salary" value="" /></td>
                <td>@Html.ValidationMessage("Salary")</td>
            </tr>
            <tr>
                <td>
                    <input type="submit" name="BtnSave" value="Save Employee" />
                    <input type="submit" name="BtnSave" value="Cancel" />
                </td>
            </tr>
           </table>
        </form>
    </div>
</body>
</html>

备注：@Html.ValidationMessage表述验收字段异常时，显示异常提示信息。

后台Action代码：

      public ActionResult SaveEmployee(Employee et, string BtnSave)
        {
            switch (BtnSave)
            {
                case "Save Employee":
                    if (ModelState.IsValid)
                    {
                        EmployeeBusinessLayer empbal = new EmployeeBusinessLayer();
                        empbal.SaveEmployee(et);
                        return RedirectToAction("Index");
                    }
                    else
                    {
                        return View("CreateEmployee");
                    }
                case "Cancel":
                //    RedirectToAction("index");
                    return RedirectToAction("Index");                                      
            }
            return new EmptyResult();
        }

备注：ModelState.IsValid表述Model字段验证是否有效

二、自定义服务端验证

1、新建自定义类：

public class FirstNameValidation : ValidationAttribute
    {
        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            if (value == null)
            {
                return new ValidationResult("Please Provide First Name");
            }
            else
            {
                if (value.ToString().Contains("@"))
                {
                    return new ValidationResult("First Name should not contain @");
                }
            }
            return ValidationResult.Success;
        }
    }

2、使用自定义验证类型

 public class Employee
    {
        [Key]
        public int EmployeeId { get; set; }

        [Required(ErrorMessage = "Enter First Name"), StringLength(50), FirstNameValidation]
        public string FirstName { get; set; }

        public int Salary { get; set; }
    }

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原文地址：https://www.cnblogs.com/xibei666/p/4989646.html