Angular2 - Validators.compose

Question

我遇到Validators.compose功能问题（没有错误，只是没有验证）

这是我的代码：

  var validators = ()=> {
           var validatorArr = [];                
           validatorArr.push(Validators.required);
           validatorArr.push(Validators.maxLength(column.max));
           return Validators.compose(validatorArr);
    };
  var ctrl: Control = new Control(row.items[column.mapper], validators);
  row.form.addControl(column.mapper, ctrl);

当我放置Validators.required而不是validators函数时，验证会起作用。

Answer 1

您应该使用此代码，而不是使用回调来定义验证器：

var validatorArr = [];                
validatorArr.push(Validators.required);
validatorArr.push(Validators.maxLength(column.max));

var ctrl: Control = new Control(row.items[column.mapper], 
                   Validators.compose(validatorArr));
row.form.addControl(column.mapper, ctrl);

Control构造函数的第二个参数对应于可以使用compose方法创建的函数...

Answer 2

只使用它而不使用箭头功能：

new Control(row.items[column.mapper],Validators.compose([Validators.required, Validators.minLength(4)]));

或

var validators = ()=> {
     return Validators.compose([Validators.required, Validators.minLength(4)]);
}

new Control(row.items[column.mapper], validators());

Answer 3

Control构造函数需要private class LoginTask extends AsyncTask<Void, Void, Void> { @Override protected void onPreExecute() { super.onPreExecute(); progressDialog = new ProgressDialog(StartActivity.this); progressDialog.setTitle(“please wait.."); progressDialog.setMessage(“authorizing..."); progressDialog.setCancelable(false); progressDialog.show(); } @Override protected Void doInBackground(Void... params) { mFirebase.authWithPassword(email, password, new Firebase.AuthResultHandler() { @Override public void onAuthenticated(AuthData authData) { // System.out.println("User ID: " + authData.getUid() + ", Provider: " + authData.getProvider()); Intent intent2 = new Intent(StartActivity.this, MainActivity.class); startActivity(intent2); finish(); } @Override public void onAuthenticationError(FirebaseError firebaseError) { // error encountered switch (firebaseError.getCode()) { case FirebaseError.USER_DOES_NOT_EXIST: // handle a non existing user Toast.makeText(getApplicationContext(), getString(R.string.error_user_not_exist) Toast.LENGTH_LONG).show(); break; case FirebaseError.INVALID_PASSWORD: // handle an invalid password Toast.makeText(getApplicationContext(), getString(R.string.error_invalid_password) Toast.LENGTH_LONG).show(); break; default: // handle other errors Toast.makeText(getApplicationContext(), getString(R.string.error_reset_password), Toast.LENGTH_LONG).show(); break; } } }); return null; } @Override protected void onPostExecute(Void result) { super.onPostExecute(result); progressDialog.dismiss(); } } 作为参数。 ValidatorFn采用Validators.compose()数组并返回一个ValidatorFn。但是你没有传递ValidatorFn作为论据。你传递的函数在被调用时返回ValidatorFn。

用

替换你的代码

ValidatorFn

或者，更短：

var validatorArr = [];                
validatorArr.push(Validators.required);
validatorArr.push(Validators.maxLength(column.max));
var validatorFn = Validators.compose(validatorArr);

var ctrl: Control = new Control(row.items[column.mapper], validatorFn);
row.form.addControl(column.mapper, ctrl);