WPF使用MVVM时，表单验证
错误提示模板：
应用场景描述：表单中TextBox数据验证条件依赖其他TextBox数据（例：腹板T<0.5*底板W）。
问题1：先录入腹板T数据，后录入底板W数据，不能触发腹板T 数据验证。
解决方法1：底板W加入和腹板T相关的验证，实现双向关联验证。优点，解决方式简单；缺点，用户体验差，增加表验证逻辑复杂性（整个表单校验时，校验失败，2选1提示数据内容）。
方法2：终端校验，保存按钮触发整个表单校验。优点：减少表单验证条件。缺点：验证条件依赖其他TextBox数据的校验，需要保存按钮触发校验提示。
问题2：表单验证失败，保存按钮不提交数据。（能力原因，没有找到ViewModel中校验整个表单的方式(╯︵╰)，有大神请赐教。）
方法1：cs代码中添加保存按钮Click事件，返回整个表单验证结果给ViewModel。（关键内容校验控件的 ((TextBox)controlName).GetBindingExpression(TextBox.TextProperty).UpdateTarget()）
ViewModel代码：
public class WorksManageViewModel : NotificationObject, IDataErrorInfo
{
///
/// 底板厚
///
public decimal H_H
{
get { return MainSelect.H_H; }
set { MainSelect.H_H = value; this.RaisePropertyChanged("H_H"); }
}
///
/// 底板宽
///
public decimal H_B
{
get { return MainSelect.H_B; }
set { MainSelect.H_B = value; this.RaisePropertyChanged("H_B");}
}
///
/// 腹板厚
///
public decimal H_T2
{
get { return MainSelect.H_T2; }
set { MainSelect.H_T2 = value; this.RaisePropertyChanged("H_T2"); }
}
///
/// 腹板宽
///
public decimal H_D
{
get { return MainSelect.H_D; }
set { MainSelect.H_D = value; this.RaisePropertyChanged("H_D"); }
}
///
/// 面板厚
///
public decimal B_H1
{
get { return MainSelect.B_H1; }
set { MainSelect.B_H1 = value; this.RaisePropertyChanged("B_H1");}
}
///
/// 面板宽
///
public decimal B_H2
{
get { return MainSelect.B_H2; }
set { MainSelect.B_H2 = value; this.RaisePropertyChanged("B_H2"); }
}
///
/// 箱体长度
///
public decimal H_T1
{
get { return MainSelect.H_T1; }
set { MainSelect.H_T1 = value; this.RaisePropertyChanged("H_T1"); }
}
public string this[string columnName]
{
get { return GetErrorFor(columnName); }
}
private string _error;
public string Error
{
get { return _error; }
set { _error = value; }
}
///
/// 校验方式
///
///
/// cs文件代码：
private void saveButton_Click(object sender, RoutedEventArgs e)
{
((WorksManageViewModel)this.DataContext).IsValid = IsValid(this);
}
// Validate all dependency objects in a window
bool IsValid(DependencyObject node)
{
// Check if dependency object was passed
if (node != null)
{
//Check DependencyObject is TextBox
//NOTE：Update DataSource Binding
if (node is TextBox)
{
BindingExpression binding = ((TextBox)node).GetBindingExpression(TextBox.TextProperty);
binding.UpdateTarget();
}
// Check if dependency object is valid.
// NOTE: Validation.GetHasError works for controls that have validation rules attached
bool isValid = !Validation.GetHasError(node);
if (!isValid)
{
// If the dependency object is invalid, and it can receive the focus,
// set the focus
if (node is IInputElement) Keyboard.Focus((IInputElement)node);
return false;
}
}
// If this dependency object is valid, check all child dependency objects
foreach (object subnode in LogicalTreeHelper.GetChildren(node))
{
if (subnode is DependencyObject)
{
// If a child dependency object is invalid, return false immediately,
// otherwise keep checking
if (IsValid((DependencyObject)subnode) == false) return false;
}
}
// All dependency objects are valid
return true;
}