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我有兩個UserControls Payroll和TabLayout。工資單包含工具欄和TabControl，TabLayout包含網格。 Payroll中的TabControl的TabItems通過我的MainViewModel中的ObservableCollection通過TabLayout進行填充。wpf - 防止重複信息MVVM
大約一小時前，我問了這個問題：WPF Unable to retrieve binding values MVVM，並得到解決。
現在我遇到了一個問題，因爲ViewModel現在是一個實例，一個Tab中的信息正在被轉移到另一個。因此所有標籤顯示相同的東西。
如果我爲每個選項卡創建ViewModel的新實例，那麼我將無法再檢索綁定值。
MainViewModel：
namespace OcelotPayroll.ViewModel
{
public class MainViewModel : ViewModelBase
{
public ObservableCollection<WorkspaceViewModel> Workspaces { get; set; }
public MainViewModel()
{
Workspaces = new ObservableCollection<WorkspaceViewModel>();
}
private DelegateCommand _newWorkspaceCommand;
public ICommand NewWorkspaceCommand
{
get { return _newWorkspaceCommand ?? (_newWorkspaceCommand = new DelegateCommand(NewWorkspace)); }
}
private void NewWorkspace()
{
var workspace = new WorkspaceViewModel
{
LoadedControl = new TabLayout() { DataContext = this }
};
Workspaces.Add(workspace);
SelectedIndex = Workspaces.IndexOf(workspace);
}
}
}
薪資DataContext設置：
public Payroll()
{
InitializeComponent();
DataContext = new PayslipModel();
}
PayslipModel/VM：
namespace OcelotPayroll
{
public class PayslipModel : EmployeeModel
{
private decimal _amount;
public decimal Amount
{
get
{
return _amount;
}
set
{
_amount = value;
OnPropertyChanged("Amount");
}
}
public string NisName
{
get
{
return _nis;
}
set
{
_nis = value;
OnPropertyChanged("NisName");
}
}
public string EdTaxName
{
get
{
return _edtax;
}
set
{
_edtax = value;
OnPropertyChanged();
}
}
public string NhtName
{
get
{
return _nht;
}
set
{
_nht = value;
OnPropertyChanged();
}
}
public string PayeName
{
get
{
return _paye;
}
set
{
_paye = value;
OnPropertyChanged();
}
}
public string NisVal
{
get
{
return _nisVal;
}
set
{
_nisVal = value;
OnPropertyChanged();
}
}
public string EdTaxVal
{
get
{
return _edVal;
}
set
{
_edVal = value;
OnPropertyChanged();
}
}
public string NhtVal
{
get
{
return _nhtVal;
}
set
{
_nhtVal = value;
OnPropertyChanged();
}
}
public string PayeVal
{
get
{
return _payeVal;
}
set
{
_payeVal = value;
OnPropertyChanged();
}
}
public decimal StautoryIncome
{
get
{
return statIncome;
}
set
{
statIncome = value;
}
}
public string TotalDeduction
{
get
{
return totalDed;
}
set
{
totalDed = value;
OnPropertyChanged();
}
}
public string NetPay
{
get
{
return _netpay;
}
set
{
_netpay = value;
OnPropertyChanged();
}
}
public bool NisChecked
{
get
{
return nisIsChecked;
}
set
{
nisIsChecked = value;
OnPropertyChanged("NisChecked");
CalcNis();
}
}
public bool EdTaxChecked
{
get
{
return edtaxIsChecked;
}
set
{
edtaxIsChecked = value;
OnPropertyChanged();
CalcEdTax();
}
}
public bool NhtChecked
{
get
{
return nhtIsChecked;
}
set
{
nhtIsChecked = value;
OnPropertyChanged();
CalcNht();
}
}
public bool PayeChecked
{
get
{
return payeIsChecked;
}
set
{
payeIsChecked = value;
OnPropertyChanged();
CalcPaye();
}
}
public bool LevyChecked
{
get
{
return levyIsChecked;
}
set
{
levyIsChecked = value;
OnPropertyChanged();
CalcLevy();
}
}
public bool WeeklyChecked
{
get
{
return wklyIsChecked;
}
set
{
wklyIsChecked = value;
OnPropertyChanged();
}
}
public bool FnChecked
{
get
{
return fnIsChecked;
}
set
{
if (fnIsChecked == value)
return;
fnIsChecked = value;
OnPropertyChanged();
}
}
public bool MonthlyChecked
{
get
{
return monthlyIsChecked;
}
set
{
if (monthlyIsChecked == value)
return;
monthlyIsChecked = value;
OnPropertyChanged();
}
}
private DateTime _date;
public DateTime Date
{
get
{
return _date;
}
set
{
_date = value;
}
}
private string _annualGross;
public string AnnualGross
{
get
{
return _annualGross;
}
set
{
_annualGross = value;
OnPropertyChanged();
}
}
private string _annualNis;
public string AnnualNis
{
get
{
return _annualNis;
}
set
{
_annualNis = value;
OnPropertyChanged();
}
}
private string _annualNht;
public string AnnualNht
{
get
{
return _annualNht;
}
set
{
_annualNht = value;
OnPropertyChanged();
}
}
private string _annualEdtax;
public string AnnualEdTax
{
get
{
return _annualEdtax;
}
set
{
_annualEdtax = value;
OnPropertyChanged();
}
}
private string _annualPaye;
public string AnnualPaye
{
get
{
return _annualPaye;
}
set
{
_annualPaye = value;
OnPropertyChanged();
}
}
public PayslipModel()
{
Date = DateTime.Today.Date;
SelectAll = new DelegateCommand(Select,() => CanSelect);
UnSelectAll = new DelegateCommand(UnSelect,() => CanUnSelect);
SaveToDatabase = new DelegateCommand(Save,() => CanSave);
scon = new MichaelAllenEntities();
}
public ICommand SelectAll
{
get; set;
}
private bool CanSelect
{
get { return Hide1 = true; }
}
private void Select()
{
if (Hide1 == true)
{
NisChecked = true;
EdTaxChecked = true;
NhtChecked = true;
PayeChecked = true;
}
}
public ICommand UnSelectAll
{
get; set;
}
private bool CanUnSelect
{
get { return Hide1 = true; }
}
private void UnSelect()
{
if (Hide1 == true)
{
NisChecked = false;
EdTaxChecked = false;
NhtChecked = false;
PayeChecked = false;
}
}
public ICommand SaveToDatabase
{
get; set;
}
private bool CanSave
{
get { return Workspaces.Count > 0; }
}
private async void Save()
{
try
{
var salary = new SalaryInfo
{
EmpId = SelectedEmployee.EmpId,
EmpName = SelectedEmployee.EmpName,
NIS = decimal.Parse(NisVal.ToString()),
NHT = decimal.Parse(NhtVal.ToString()),
EdTax = decimal.Parse(EdTaxVal.ToString()),
PAYE = decimal.Parse(PayeVal.ToString()),
TotalTax = decimal.Parse(TotalDeduction.ToString()),
StatutoryIncome = StautoryIncome,
GrossPay = Amount,
NetPay = decimal.Parse(NetPay.ToString()),
Date = Date,
Earnings = Earnings,
PayPeriod = SelectedValueOne.Value
};
scon.SalaryInfoes.Add(salary);
scon.SaveChanges();
}
catch (DbEntityValidationException ex)
{
}
catch(Exception ex)
{
var exceptionDialog = new MessageDialog
{
Message = { Text = string.Format("{0}", ex) }
};
await DialogHost.Show(exceptionDialog, "RootDialog");
}
}
private bool _hide1 = true;
public bool Hide1
{
get
{
return _hide1;
}
set
{
_hide1 = value;
OnPropertyChanged();
}
}
private bool _hide2 = false;
public bool Hide2
{
get
{
return _hide2;
}
set
{
_hide2 = value;
OnPropertyChanged();
}
}
private EmployeeInfo _selectedEmployee;
public new EmployeeInfo SelectedEmployee
{
get { return _selectedEmployee; }
set
{
_selectedEmployee = value;
OnPropertyChanged();
if(SelectedEmployee.EmployedUnder == "Michael Allen")
{
Hide1 = true;
Hide2 = false;
}
if(SelectedEmployee.EmployedUnder == "Barachel Ltd")
{
Hide2 = true;
Hide1 = false;
}
}
}
private string _hours;
public string Hours
{
get
{
return _hours;
}
set
{
_hours = value;
OnPropertyChanged();
}
}
private string _rate;
public string Rate
{
get
{
return _rate;
}
set
{
_rate = value;
OnPropertyChanged();
if (Rate != string.Empty || Hours != string.Empty)
{
Amount = decimal.Parse((double.Parse(Hours.ToString()) * double.Parse(Rate.ToString())).ToString());
}else
{
Amount = 0;
}
}
}
private string _selectedDate;
public string SelectedDate
{
get
{
return _selectedDate;
}
set
{
_selectedDate = value;
OnPropertyChanged();
}
}
private string _earnings;
public string Earnings
{
get
{
return _earnings;
}
set
{
_earnings = value;
OnPropertyChanged();
}
}
#region Calculations
public async void CalcNis()
{
try
{
float nis = 0;
NisName = "N.I.S.";
SqlConnection con = new SqlConnection(scon.Database.Connection.ConnectionString);
con.Open();
SqlCommand cmd = new SqlCommand("select NIS from Deductions where TaxId='1'", con);
SqlDataReader sdr = cmd.ExecuteReader();
while (sdr.Read())
{
nis = float.Parse(sdr.GetValue(0).ToString());
}
con.Close();
if (Amount != 0)
{
NisVal = (decimal.Parse(Amount.ToString()) * decimal.Parse(nis.ToString())).ToString("N2");
StautoryIncome = (decimal.Parse(Amount.ToString()) - decimal.Parse(NisVal.ToString()));
}
}
catch(Exception ex)
{
var exceptionDialog = new MessageDialog
{
Message = { Text = ex.ToString() }
};
await DialogHost.Show(exceptionDialog, "RootDialog");
}
}
public async void CalcLevy()
{
try
{
if(LevyChecked == true)
{
float levy = 0;
NisName = "Contractor's Levy";
SqlConnection con = new SqlConnection(scon.Database.Connection.ConnectionString);
con.Open();
SqlCommand cmd = new SqlCommand("select ContractorLevy from Deductions where TaxId='1'", con);
SqlDataReader sdr = cmd.ExecuteReader();
while (sdr.Read())
{
levy = float.Parse(sdr.GetValue(0).ToString());
}
con.Close();
if (Amount != 0)
{
NisVal = (double.Parse(Amount.ToString()) * double.Parse(levy.ToString())).ToString("N2");
TotalDeduction = double.Parse(NisVal.ToString()).ToString("N2");
NetPay = (double.Parse(Amount.ToString()) - double.Parse(NisVal.ToString())).ToString("N2");
}
}else
if(LevyChecked == false)
{
NisVal = string.Empty;
TotalDeduction = string.Empty;
NetPay = string.Empty;
}
}
catch (Exception ex)
{
var exceptionDialog = new MessageDialog
{
Message = { Text = ex.ToString() }
};
await DialogHost.Show(exceptionDialog, "RootDialog");
}
}
public async void CalcEdTax()
{
try
{
float edtax = 0;
EdTaxName = "EDUCATION TAX";
SqlConnection con = new SqlConnection(scon.Database.Connection.ConnectionString);
con.Open();
SqlCommand cmd = new SqlCommand("select EdTax from Deductions where TaxId='1'", con);
SqlDataReader sdr = cmd.ExecuteReader();
while (sdr.Read())
{
edtax = float.Parse(sdr.GetValue(0).ToString());
}
con.Close();
if (EdTaxName != string.Empty)
{
if (StautoryIncome != 0)
{
EdTaxVal = (statIncome * decimal.Parse(edtax.ToString())).ToString("N2");
}
}
}
catch (Exception ex)
{
var exceptionDialog = new MessageDialog
{
Message = { Text = ex.ToString() }
};
await DialogHost.Show(exceptionDialog, "RootDialog");
}
}
public async void CalcNht()
{
try
{
float nht = 0;
NhtName = "N.H.T.";
SqlConnection con = new SqlConnection(scon.Database.Connection.ConnectionString);
con.Open();
SqlCommand cmd = new SqlCommand("select NHT from Deductions where TaxId='1'", con);
SqlDataReader sdr = cmd.ExecuteReader();
while (sdr.Read())
{
nht = float.Parse(sdr.GetValue(0).ToString());
}
con.Close();
if (Amount != 0)
{
NhtVal = (decimal.Parse(Amount.ToString()) * decimal.Parse(nht.ToString())).ToString("N2");
}
}
catch (Exception ex)
{
var exceptionDialog = new MessageDialog
{
Message = { Text = ex.ToString() }
};
await DialogHost.Show(exceptionDialog, "RootDialog");
}
}
private decimal _totalAmount;
public decimal TotalAmount
{
get
{
return _totalAmount;
}
set
{
_totalAmount = value;
OnPropertyChanged();
}
}
public async void CalcPaye()
{
try
{
float paye = 0;
decimal threshold = 0, taxable = 0, above = 0.3M;
if (PayeChecked == true)
{
PayeName = "P.A.Y.E.";
SqlConnection con = new SqlConnection(scon.Database.Connection.ConnectionString);
con.Open();
SqlCommand cmd = new SqlCommand("select PAYE, FNTaxThreshold from Deductions where TaxId='1'", con);
SqlDataReader sdr = cmd.ExecuteReader();
if (Amount != 0)
{
while (sdr.Read())
{
paye = float.Parse(sdr.GetValue(0).ToString());
threshold = decimal.Parse(sdr.GetValue(1).ToString());
}
con.Close();
//
//Fortnightly
//
if (FnChecked == true)
{
if (threshold <= decimal.Parse(Amount.ToString()))
{
if ((double.Parse(Amount.ToString()) * 2) * 12 <= 796536)
{
taxable = StautoryIncome - threshold;
PayeVal = (taxable * 0).ToString("N2");
}
else if ((double.Parse(Amount.ToString()) * 2) * 12 >= 796536 && (double.Parse(Amount.ToString()) * 2) * 12 <= 6000000)
{
taxable = StautoryIncome - threshold;
PayeVal = (taxable * decimal.Parse(paye.ToString())).ToString("N2");
}
else if ((double.Parse(Amount.ToString()) * 2) * 12 > 6000000)
{
taxable = StautoryIncome - threshold;
PayeVal = (taxable * above).ToString("N2");
}
}
}
//
//Monthly Checked
//
if (MonthlyChecked == true)
{
con.Open();
cmd = new SqlCommand("select MonthlyThreshold from Deductions where TaxId='1'", con);
sdr = cmd.ExecuteReader();
while (sdr.Read())
{
threshold = decimal.Parse(sdr.GetValue(0).ToString());
}
con.Close();
if (threshold <= decimal.Parse(Amount.ToString()))
{
if ((double.Parse(Amount.ToString()) * 2) * 12 <= 796536)
{
taxable = StautoryIncome - threshold;
PayeVal = (taxable * 0).ToString("N2");
}
else if ((double.Parse(Amount.ToString()) * 2) * 12 >= 796536 && (double.Parse(Amount.ToString()) * 2) * 12 <= 6000000)
{
taxable = StautoryIncome - threshold;
PayeVal = (taxable * decimal.Parse(paye.ToString())).ToString("N2");
}
else if ((double.Parse(Amount.ToString()) * 2) * 12 > 6000000)
{
taxable = StautoryIncome - threshold;
PayeVal = (taxable * above).ToString("N2");
}
}
else if (threshold > decimal.Parse(Amount.ToString()))
{
PayeVal = (0).ToString("N2");
}
}
}
if (EdTaxVal != string.Empty || NhtVal != string.Empty || NisVal != string.Empty || PayeVal != string.Empty)
{
double total = 0;
total = double.Parse(NisVal.ToString()) + double.Parse(PayeVal.ToString()) + double.Parse(NhtVal.ToString()) + double.Parse(EdTaxVal.ToString());
TotalDeduction = total.ToString("N2");
NetPay = (double.Parse(Amount.ToString()) - total).ToString("N2");
}
}
else if(PayeChecked == false)
{
if (PayeVal != string.Empty)
{
PayeName = string.Empty;
taxable += decimal.Parse(PayeVal.ToString());
StautoryIncome += taxable;
}
}
}
catch (Exception ex)
{
var exceptionDialog = new MessageDialog
{
Message = { Text = ex.ToString() }
};
await DialogHost.Show(exceptionDialog, "RootDialog");
}
}
#endregion
}
}
MVVM是指獨立的UI層和數據層，你看像你將它們結合起來。我現在沒有時間寫完整答案+示例，但是您可以看到如何在TabControl結構中使用MVVM的示例[此處]（https://rachel53461.wordpress.com/2011/12/18/導航與 - MVVM-2 /）。我唯一期望看到DataContext集的地方是應用程序啓動的初始綁定。任何地方都會向我發送紅色警告標誌。 – Rachel
@Rachel，你提供的例子並不是我正在尋找的，你對DataContext是正確的。我現在已經刪除了它 – bruh1234