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));
}
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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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