mvc中动态给一个Model类的属性设置验证

原文:
mvc中动态给一个Model类的属性设置验证

在mvc中有自带的验证机制，比如如果某个字段的类型是数字或者日期，那么用户在输入汉字或者英文字符时，那么编译器会自动验证并提示用户格式不正确，不过这样的验证毕竟功能有限，那么就需要我们自己进行定制验证。

假设有Model类：class Dinners{

private string Title;

private System.DateTime EventDate;

private string Description;

private string HostedBy;

private string ContactPhone;

private string Address;

private string Country;

private double Latitude;

private double Longitude;

}

这里需要对该类的每个属性都加上不可为空的约束，并对电话号码、日期做验证。代码如下：

public partial class Dinners

{

public bool IsValid

{

get { return (GetRuleViolations().Count() == 0); }

}

public IEnumerable<RuleViolation> GetRuleViolations()

{

if (String.IsNullOrEmpty(Title))

{

yield return new RuleViolation("Title required", "Title");

}

if (String.IsNullOrEmpty(Description))

{

yield return new RuleViolation("Description required", "Description");

}

if (String.IsNullOrEmpty(HostedBy))

{

yield return new RuleViolation("HostedBy required", "HostedBy");

}

if (String.IsNullOrEmpty(Address))

{

yield return new RuleViolation("Address required", "Address");

}

if (String.IsNullOrEmpty(Country))

{

yield return new RuleViolation("Country required", "Country");

}

if (String.IsNullOrEmpty(ContactPhone))

{

yield return new RuleViolation("Phone# required", "ContactPhone");

}

//这里引用了类PhoneValidator(自定义验证类，不再详述）

if (!PhoneValidator.IsValidNumber(ContactPhone, Country))

{

yield return new RuleViolation("Phone# does not match country", "ContactPhone");

}

yield break;

}

partial void OnValidate(ChangeAction action)

{

if (!IsValid)

{

throw new ApplicationException("Rule violations prevent saving");

}

}

}

public class RuleViolation

{

public string ErrorMessage { get; private set; }

public string PropertyName { get; private set; }

public RuleViolation(string errorMessage, string propertyName)

{

ErrorMessage = errorMessage;

PropertyName = propertyName;

}

}

前台验证代码：

<h2>Edit Dinner</h2>

<%=Html.ValidationSummary("Please crrect the errors and try again.") %>

<% using (Html.BeginForm()) {%>

<fieldset>

<p>

<label for="Title">Dinner Title:</label>

<%=Html.TextBox("Title") %>

<%=Html.ValidationMessage("Title","*") %>

</p>

<p>

<label for="EventDate">EventDate:</label>

<%=Html.TextBox("EventDate",string.Format("{0:g}",Model.EventDate)) %>

<%=Html.ValidationMessage("EventDate","*") %>

</p>

<p>

<label for="Description">Description:</label>

<%=Html.TextArea("Description") %>

<%=Html.ValidationMessage("Description","*") %>

</p>

<p>

<label for="Address">Address:</label>

<%=Html.TextArea("Address") %>

<%=Html.ValidationMessage("Address","*") %>

</p>

<p>

<label for="Country">Country:</label>

<%=Html.TextBox("Country") %>

<%=Html.ValidationMessage("Country","*") %>

</p>

<p>

<label for="ContactPhone">ContactPhone #:</label>

<%=Html.TextBox("ContactPhone") %>

<%=Html.ValidationMessage("ContactPhone","*") %>

</p>

<p>

<label for="Latitude">Latitude:</label>

<%=Html.TextBox("Latitude") %>

<%=Html.ValidationMessage("Latitude","*") %>

</p>

<p>

<label for="Longitude">Longitude:</label>

<%=Html.TextBox("Longitude") %>

<%=Html.ValidationMessage("Longitude","*") %>

</p>

<p>

<input type="submit" value="Save" />

</p>

</fieldset>

<% } %>

<div>

<%= Html.ActionLink("Back to List", "Index") %>

</div>

注：代码来自教程《一步一步学习asp.net mvc》