我有一個實現INotifyPropertyChanged的父類,父類有多個孩子。孩子們有不同的屬性,都稱爲PropertyChanged。我想添加驗證,但我真的不想爲每個子類都寫驗證。驗證規則是從數據庫提供的,所以我最終必須爲每個孩子抽取驗證規則,然後根據規則檢查值。如果我這樣做了,我認爲它會有太多冗餘代碼,並且我想將它放在父級別上,因爲PropertyChanged會觸發值本身的字符串值。如何爲實現不同屬性的子類提供驗證?
是否有可能對父類有驗證方法,所以我不必爲每個子類寫一個驗證方法?請注意,每個孩子班的屬性都不相同。
下面是我現在有,在兒童班驗證。
public Parent : INotifyChanged {
/// <summary>
/// Occurs when a property is changed
/// </summary>
public event PropertyChangedEventHandler PropertyChanged;
/// <summary>
/// Raises the <see cref="PropertyChanged"/> for a given
/// property.
/// </summary>
/// <param name="propertyName"></param>
protected void OnPropertyChanged(String propertyName) {
// Get the hanlder
PropertyChangedEventHandler handler = this.PropertyChanged;
// Check that the event handler is not null
if(null != handler) {
// Fire the event
handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
Child1類:
public Child1 : Parent, IDataErrorInfo {
private Dictionary<string, string> m_validationErrors = new Dictionary<string, string>();
private void Validate() {
this.RemoveError("Child1Description");
if(!Regex.IsMatch(Child1Description, "^([a-zA-Z '-]+)$") && !String.IsNullOrWhiteSpace(Description)) {
this.AddError("Child1Description", "Only non-numerics allowed.");
}
}
private void AddError(string columnName, string msg) {
if(!m_validationErrors.ContainsKey(columnName)) {
m_validationErrors.Add(columnName, msg);
}
}
private void RemoveError(string columnName) {
if(m_validationErrors.ContainsKey(columnName)) {
m_validationErrors.Remove(columnName);
}
}
public string Error {
get {
if(m_validationErrors.Count > 0) {
return "Field data is invalid.";
}
else return null;
}
}
public string this[string columnName] {
get {
if(m_validationErrors.ContainsKey(columnName)) {
return m_validationErrors[columnName];
}
else {
return null;
}
}
}
/// <summary>
/// Description of the air entity
/// </summary>
public string Child1Description {
get {
return Child1description;
}
set {
description = value;
Validate();
OnPropertyChanged("Child1Description");
}
}
}
CHILD2類:
public Child2 : Parent, IDataErrorInfo {
private Dictionary<string, string> m_validationErrors = new Dictionary<string, string>();
private void Validate() {
this.RemoveError("Child2Description");
if(!Regex.IsMatch(Child2Description, "^([a-zA-Z '-]+)$") && !String.IsNullOrWhiteSpace(Description)) {
this.AddError("Child2Description", "Only non-numerics allowed.");
}
}
private void AddError(string columnName, string msg) {
if(!m_validationErrors.ContainsKey(columnName)) {
m_validationErrors.Add(columnName, msg);
}
}
private void RemoveError(string columnName) {
if(m_validationErrors.ContainsKey(columnName)) {
m_validationErrors.Remove(columnName);
}
}
public string Error {
get {
if(m_validationErrors.Count > 0) {
return "Field data is invalid.";
}
else return null;
}
}
public string this[string columnName] {
get {
if(m_validationErrors.ContainsKey(columnName)) {
return m_validationErrors[columnName];
}
else {
return null;
}
}
}
/// <summary>
/// Description of the air entity
/// </summary>
public string Child2Description {
get {
return Child2description;
}
set {
description = value;
Validate();
OnPropertyChanged("Child2Description");
}
}
}
問:是否可以對父類使用驗證方法?答:當然。爲什麼不?你的問題到底是什麼?你可以發佈任何代碼嗎? – paulsm4
@ paulsm4對不起,正試圖清理它。已添加代碼。 –