WPF data binding delay

Question

I am creating an app in WPF. I have created a form which have text boxes for data entry, there is a save button which will save the data. I am using data binding to properties. The problem I face is that when the user clicks on the save button very quickly after entering into the textbox, I get a null value even though the textbox is containing text. Dont worry about the path of data binding and all bcoz if I click on save after a time delay, the values are fetched correctly - so no binding issues. My queries are:

1) Should I be using binding at all on text boxes which doesnt require validations, coz i am using IDataErrorInfo and just do like this: string value = txtBox_abc.Text;

2) I there to delay the save button click, so that I collect values from the text boxes only after all the properties have been successfully bounded to the views - is there a way at all to know this.

Binding class:

namespace Trans_It.Binding
{
    class B_Ledger : IDataErrorInfo
    {
        public string LedgerName { get; set; }
        public string LedgerCont1 { get; set; }
        public string LedgerCont2 { get; set; }
        public string LedgerEmail1 { get; set; }
        public string LedgerEmail2 { get; set; }
        public string LedgerAdd1 { get; set; }
        public string LedgerAdd2 { get; set; }
        public string LedgerCity { get; set; }
        public string LedgerPincode { get; set; }

        public string Error
        {
            get { throw new NotImplementedException(); }
        }

        public string this[string colName]
        { 
            get
            {
                string result = null;

                if (colName == "LedgerName")
                {
                    if (string.IsNullOrEmpty(LedgerName))
                    {
                        result = "Ledger name mandatory!";
                    }
                    else if(string.IsNullOrEmpty(LedgerName.Trim()))
                    {
                        result = "Invalid Ledger name!";
                    }
                }
                if (colName == "LedgerCont1")
                {
                    if (string.IsNullOrEmpty(LedgerCont1))
                    {
                        result = "Provide atleast one contact no.!";
                    }
                    else if (LedgerCont1.Length < 8)
                    {
                        result = "Contact no. should be of atleast 8 characters!";
                    }

                }

                return result;
            }

        }
    }
}

In this file, in click handler of the button, I save the fields to database. Suppose even if I have value in my textBox, but because of the delay, I get an error message like:

Message: Parameterized query expects a parameter value which was not supplied. Parameter name: @led_pincode

And if I wait for 3-4 seconds, The transaction is successful. It means its just because of the delay, isn't it??

The xaml.cs code behind of my page where i face the problem:

namespace Trans_It.Pages
{
    /// 
    /// Interaction logic for Page_AddLedger.xaml
    /// 
    public partial class Page_AddLedger : Page
    {
        B_Ledger _ledger = new B_Ledger();
        private int _errors = 0;

        public Page_AddLedger()
        {
            InitializeComponent();
            grid_ledDetails.DataContext = _ledger;
        }

        private void Confirm_CanExecute(object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = _errors == 0;
            e.Handled = true;
        }

        private void Confirm_Executed(object sender, ExecutedRoutedEventArgs e)
        {
            _ledger = new B_Ledger();
            grid_ledDetails.DataContext = _ledger;
            e.Handled = true;
        }

        private void Validation_Error(object sender, ValidationErrorEventArgs e)
        {
            if (e.Action == ValidationErrorEventAction.Added)
                _errors++;
            else
                _errors--;
        }

        private void btn_addLedger_Click(object sender, EventArgs e)
        {
            List list_insertStmnts = new List();
            list_insertStmnts.Add(getPartyInsertStatement());

            bool lb_txnSuccess = M_DbMain.performInsertTxn(list_insertStmnts);

            if (lb_txnSuccess)
            {
                MessageBox.Show("Txn Success");
            }
            else
            {
                MessageBox.Show("Txn Failure");
            }

            // 
            //this.NavigationService.GoBack();
            // 
        }

        private SqlCeCommand getPartyInsertStatement()
        {
            string ls_insertStmnt;

            ls_insertStmnt = "INSERT INTO " + M_LedgerMaster.TABLE_NAME +
                                "(" +
                                M_LedgerMaster.LED_NAME + ", " +
                                M_LedgerMaster.LED_CONTACT1 + ", " +
                                M_LedgerMaster.LED_CONTACT2 + ", " +
                                M_LedgerMaster.LED_EMAIL1 + ", " +
                                M_LedgerMaster.LED_EMAIL2 + ", " +
                                M_LedgerMaster.LED_ADD1 + ", " +
                                M_LedgerMaster.LED_ADD2 + ", " +
                                M_LedgerMaster.LED_CITY + ", " +
                                M_LedgerMaster.LED_PINCODE +
                                ")" +
                                " VALUES " +
                                "(" +
                                "@" + M_LedgerMaster.LED_NAME + ", " +
                                "@" + M_LedgerMaster.LED_CONTACT1 + ", " +
                                "@" + M_LedgerMaster.LED_CONTACT2 + ", " +
                                "@" + M_LedgerMaster.LED_EMAIL1 + ", " +
                                "@" + M_LedgerMaster.LED_EMAIL2 + ", " +
                                "@" + M_LedgerMaster.LED_ADD1 + ", " +
                                "@" + M_LedgerMaster.LED_ADD2 + ", " +
                                "@" + M_LedgerMaster.LED_CITY + ", " +
                                "@" + M_LedgerMaster.LED_PINCODE +
                                ");";

            SqlCeCommand cmd = new SqlCeCommand();

            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_NAME, _ledger.LedgerName));
            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_CONTACT1, _ledger.LedgerCont1));
            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_CONTACT2, _ledger.LedgerCont2));
            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_EMAIL1, _ledger.LedgerEmail1));
            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_EMAIL2, _ledger.LedgerEmail2));
            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_ADD1, _ledger.LedgerAdd1));
            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_ADD2, _ledger.LedgerAdd2));
            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_CITY, _ledger.LedgerCity));
            cmd.Parameters.Add(new SqlCeParameter("@" + M_LedgerMaster.LED_PINCODE, _ledger.LedgerPincode));

            cmd.CommandText = ls_insertStmnt;

            return cmd;
        }
    }
}

//////////////////////////////////////////////////////////// The .xaml file:



    
        
            
            
            
            
            
            
            
        

        
            
            
            
            
            
            
            
            
            
            
            
            
            
        

        
            
        

        
        Ledger Name
        Contact
        Email
        Address
        City And Pincode

///////////////////////////////////////////////////////////////////////

Never posted any code, so forgive me if If I am not clear. If something missing, I will surely post it.

I have read about the message queue. But cant find any solution, please help.

Cheers!! Thanks in Advance!!!!

WPF data binding delay

Answers (1)

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