LightSwitch 2011 数据字段唯一性验证方案
验证单表数据的某个字段不能输入重复值
设置实体字段唯一索引
如果不写代码,那么验证只会在用户提交[保存]数据后,会提示错误,很明显这样的用户体验并不好,因此还需要做以下步骤
添加自定义验证
- partial void UserName_Validate(EntityValidationResultsBuilder results)
- {
- // results.AddPropertyError("<错误消息>");
- bool duplicateExists = false
- switch (this.Details.EntityState)
- {
- case EntityState.Added:
- {
- //基于页面未提交数据的验证
- duplicateExists = (from item in DataWorkspace.ApplicationData.Details.GetChanges().AddedEntities.OfType<Employee>()
- where item.UserName == this.UserName && !string.IsNullOrEmpty(this.UserName)
- select item).Count() > 1 ? true : false
- //基于数据库的验证
- if (!duplicateExists)
- duplicateExists = (from Employee emp in DataWorkspace.ApplicationData.Employees.Cast<Employee>()
- where this.UserName != null &&
- string.Compare(emp.UserName, this.UserName.Trim(), StringComparison.InvariantCultureIgnoreCase) == 0
- select emp).Any();
- break
- }
- case EntityState.Modified:
- {
- duplicateExists = (from item in DataWorkspace.ApplicationData.Details.GetChanges().ModifiedEntities.OfType<Employee>()
- where item.UserName == this.UserName && !string.IsNullOrEmpty(this.UserName)
- select item).Count() > 1 ? true : false
- if (!duplicateExists)
- duplicateExists = (from Employee emp in DataWorkspace.ApplicationData.Employees.Cast<Employee>()
- where this.UserName != null &&
- string.Compare(emp.UserName, this.UserName.Trim(), StringComparison.InvariantCultureIgnoreCase) == 0
- select emp).Any();
- break
- }
- }
- if (duplicateExists)
- {
- results.AddPropertyError(string.Format("该用户[{0}]已经存在。", UserName));
- }
运行结果如下
原文链接:http://www.cnblogs.com/neozhu/archive/2011/10/19/2217221.html
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