How to resolve my apps design issues and app crashing?

Question

In my WPF app why isn't the horizontal scroll bar showing or working properly?

XAML code:

https://codeshare.io/K8vDr8

CodeBehind:

    using System.ComponentModel;  
    using OfficeOpenXml;  
    using System.Data;  
    using System;  
    using System.Collections.Generic;  
    using System.Linq;  
    using System.Windows;  
    using System.Windows.Controls;  
    using System.Windows.Data;  
    using System.Windows.Documents;  
    using System.Windows.Input;  
    using System.Windows.Media;  
      
    namespace mar22Proj  
    {  
    	public partial class Window1 : Window  
    	{  
    		private List<string> cBItems = new List<string>();  
      
    		List<string> Names = new List<string>();  
      
    		private ICollectionView view;  
      
      
    		string file_Bills = @"test.xlsx";  
      
    		private DataTable SelectExcelRows(string filename, string key)  
    		{  
    			using (ExcelPackage package = new ExcelPackage(new System.IO.FileInfo(filename), false))  
    			{  
    				ExcelWorksheet workSheet = package.Workbook.Worksheets[0];  
      
    				DataTable dtTemp = new DataTable();  
    				dtTemp.Columns.Add("Party");  
    				dtTemp.Columns.Add("Bill No.");  
    				dtTemp.Columns.Add("Bill Date");  
    				dtTemp.Columns.Add("Amount");  
    				dtTemp.Columns.Add("Due Date");  
    				dtTemp.Columns.Add("Remarks");  
    				dtTemp.Columns.Add("Payment Released on");  
      
    				for (int row = 2; row <= workSheet.Dimension.End.Row; row++)  
    				{  
    					if (String.Equals(workSheet.Cells[row, 1].Text, key, StringComparison.OrdinalIgnoreCase))  
    						FilterDGV(dtTemp, workSheet, row);  
    				};  
      
    				return dtTemp;  
    			};  
    		}  
      
    		private static void FilterDGV(DataTable tbl, ExcelWorksheet sht, int rowIndex)  
    		{  
    			var drAddItem = tbl.NewRow();  
    			tbl.Rows.Add(drAddItem);  
      
    			foreach (var column in tbl.Columns.OfType<DataColumn>())  
    			{  
    				drAddItem[column] = sht.Cells[rowIndex, column.Ordinal+1].Text;  
    			};  
    		}  
    		  
    		public static string LastRow(string fpath)  
    		{  
    			using (ExcelPackage excelPackage = new ExcelPackage(fpath))  
    			{  
      
    				ExcelWorksheet worksheet = excelPackage.Workbook.Worksheets.First();  
      
    				int lastRow = 0;  
      
    				for (int i = 2; i <= worksheet.Dimension.End.Row; i++)  
    				{  
    					if (!string.IsNullOrEmpty(worksheet.Cells["A"+i].Text))  
    					{  
    						lastRow =i;  
    					}  
    				}  
    				return lastRow.ToString();  
    			}  
    		}  
    		  
    		public Window1()  
    		{  
    			InitializeComponent();  
    			ExcelPackage.LicenseContext = OfficeOpenXml.LicenseContext.NonCommercial;  
    			  
    			using (ExcelPackage package = new ExcelPackage(new System.IO.FileInfo(file_Bills), false))  
    			{  
    				ExcelWorksheet mainSheet = package.Workbook.Worksheets.First();  
      
    				List<string> party = new List<string>();  
      
    				for (int row = 2; row <= Convert.ToInt32(LastRow(file_Bills)); row++)  
    				{  
    					if (!string.IsNullOrEmpty(mainSheet.Cells[row, 1].Text))  
    					{  
    						party.Add(mainSheet.Cells[row, 1].Text);  
    					}  
    				}  
      
      
    				foreach (var element in party.Distinct())  
    				{  
    					cBItems.Add(element);  
    				}  
      
    			}  
    			  
    			cmb.ItemsSource = cBItems;  
    			  
    			KeyboardNavigation.SetDirectionalNavigation(cmb, KeyboardNavigationMode.Cycle);  
    			view = CollectionViewSource.GetDefaultView(cBItems);  
      
    			rb1.IsChecked = true;  
    		}  
    		void window1_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)  
    		{  
    			DragMove();  
    		}  
    		void quit_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)  
    		{  
    			Close();  
    		}  
    		void cmb_KeyUp(object sender, KeyEventArgs e)  
    		{  
    			var tb = cmb.Template.FindName("PART_EditableTextBox", cmb) as System.Windows.Controls.TextBox;  
    			var val = tb.Text;  
    			var empty = string.IsNullOrEmpty(tb.Text);  
      
    			var keysToIgnore = new Key[] { Key.Down, Key.Up, Key.Enter, Key.Left, Key.Right };  
      
    			if (keysToIgnore.Contains(e.Key))  
    			{  
    				return;  
    			}  
      
    			if (empty)  
    			{  
    				view.Filter = null;  
    			}  
    			else  
    			{  
    				view.Filter = (i) =>  
    				{  
    					var str = i.ToString();  
    					return str.ToLowerInvariant().Contains(tb.Text.ToLowerInvariant());  
    				};  
    			}  
      
    			cmb.IsDropDownOpen = true;  
      
    			tb.Text = val;  
    			tb.CaretIndex = tb.Text.Length;  
    		}  
    		void cmb_SelectionChanged(object sender, SelectionChangedEventArgs e)  
    		{  
    			var results = SelectExcelRows(file_Bills, (sender as System.Windows.Controls.ComboBox).SelectedItem as string);  
      
    			dg.ItemsSource = results.DefaultView;  
    		}  
    		void maximize_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)  
    		{  
    			if (WindowState==WindowState.Normal)  
    			{  
    				WindowState=WindowState.Maximized;  
    			}  
    			else  
    				WindowState=WindowState.Normal;  
    		}  
    		void rb1_Checked(object sender, RoutedEventArgs e)  
    		{  
    			txt.Text="";  
    			txt.Focus();  
    			tblock.Text = "Enter full invoice number or a part of it";  
    		}  
    		void rb2_Checked(object sender, RoutedEventArgs e)  
    		{  
    			txt.Text="";  
    			txt.Focus();  
    			tblock.Text = "Enter a complete date (day, then month and then year)";  
    		}  
    		void rb3_Checked(object sender, RoutedEventArgs e)  
    		{  
    			txt.Text="";  
    			txt.Focus();  
    			tblock.Text = "Enter exact amount as per Invoice";  
    		}  
    		void dg_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)  
    		{  
    			e.Column = new DataGridTextColumn() {  
    				Header = e.PropertyName,  
    				SortMemberPath = e.PropertyName, //To allow for sorting on a column  
    				Binding = new Binding("[" + e.PropertyName + "]")  
    			};  
    		}  
    	}  
    }  

Also, when I try to type in the combo box the app crashes. How do I fix that as well?

Answer 1

I'm not sure what you are trying to achieve here, the error should be that the view is not instantiated. You could try to instantiate the view as needed.

I put the code List<string> party = new List<string>(); outside the method and try to add code like below .

void cmb_KeyUp(object sender, KeyEventArgs e)  
            {  
                var tb = cmb.Template.FindName("PART_EditableTextBox", cmb) as TextBox;  
                var val = tb.Text;  
                var empty = string.IsNullOrEmpty(tb.Text);  
                var keysToIgnore = new Key[] { Key.Down, Key.Up, Key.Enter, Key.Left, Key.Right };  
                if (keysToIgnore.Contains(e.Key))  
                {  
                  return;  
                }  
                if (empty)  
                {  
                view.Filter = null;  
                }  
                else  
                {  
                    view = CollectionViewSource.GetDefaultView(party);  
                    view.Filter = (i) =>  
                    {  
                        var str = i.ToString();  
                        return str.ToLowerInvariant().Contains(tb.Text.ToLowerInvariant());  
                    };  
                }  
                cmb.IsDropDownOpen = true;  
                tb.Text = val;  
             //tb.CaretIndex = tb.Text.Length;  
            }  

Update:

 <Style  
 TargetType="{x:Type DataGrid}">  
            <Setter Property="ColumnWidth"  Value="auto"></Setter>  
            <Setter Property="FontSize" Value="13"></Setter>  
        </Style>  

You could modify your dg_AutoGeneratingColumn method as needed.

void dg_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)  
            {  
                string headerName = e.Column.Header.ToString();  
            e.Column = new DataGridTextColumn()  
            {  
                Header = e.PropertyName,  
                 
                SortMemberPath = e.PropertyName, //To allow for sorting on a column  
                Binding = new Binding("[" + e.PropertyName + "]")  
                };  
                if (headerName == "Party")  
                {  
                e.Column.Width = 298;  
                }  
            //if (headerName == "Bill No.")  
            //{  
            //e.Column.Width = 148;  
            //}  
  
            if (headerName == "Bill Date")  
            {  
                e.Column.Width = 148;  
            }  
            //if (headerName == "Amount")  
            //{  
            //e.Column.Width = 148;  
            //}  
            if (headerName == "Due Date")  
                {  
                e.Column.Width = 248;  
                }  
                if (headerName == "Remarks")  
                {  
                e.Column.Width = 248;  
                }  
                if (headerName == "Payment Released on")  
                {  
                e.Column.Width = 288;  
                }  
            }  

Update 2 : You can add additional properties to Combobox to filter.

 <ComboBox	IsTextSearchEnabled="True"	IsReadOnly="False" 	IsEditable="True"	Margin="10,0"	x:Name="cmb"	Width="380"  
				Height="35"		HorizontalAlignment="Left"	VerticalAlignment="Top"		SelectionChanged="cmb_SelectionChanged"   KeyUp="cmb_KeyUp"    
                     local:ComboBox.IsFilterOnAutocompleteEnabled="True" />  


 class ComboBox : DependencyObject  
  {  
    #region IsFilterOnAutoCompleteEnabled attached property  
  
    public static readonly DependencyProperty IsFilterOnAutocompleteEnabledProperty =  
      DependencyProperty.RegisterAttached(  
        "IsFilterOnAutocompleteEnabled",  
        typeof(bool),  
        typeof(ComboBox),  
        new PropertyMetadata(default(bool), ComboBox.OnIsFilterOnAutocompleteEnabledChanged));  
  
    public static void SetIsFilterOnAutocompleteEnabled(DependencyObject attachingElement, bool value) =>  
      attachingElement.SetValue(ComboBox.IsFilterOnAutocompleteEnabledProperty, value);  
  
    public static bool GetIsFilterOnAutocompleteEnabled(DependencyObject attachingElement) =>  
      (bool)attachingElement.GetValue(ComboBox.IsFilterOnAutocompleteEnabledProperty);  
  
    #endregion  
  
    private static Dictionary<TextBox, System.Windows.Controls.ComboBox> TextBoxComboBoxMap { get; }  
    private static Dictionary<TextBox, int> TextBoxSelectionStartMap { get; }  
    private static Dictionary<System.Windows.Controls.ComboBox, TextBox> ComboBoxTextBoxMap { get; }  
    private static bool IsNavigationKeyPressed { get; set; }  
  
    static ComboBox()  
    {  
      ComboBox.TextBoxComboBoxMap = new Dictionary<TextBox, System.Windows.Controls.ComboBox>();  
      ComboBox.TextBoxSelectionStartMap = new Dictionary<TextBox, int>();  
      ComboBox.ComboBoxTextBoxMap = new Dictionary<System.Windows.Controls.ComboBox, TextBox>();  
    }  
    private static void OnIsFilterOnAutocompleteEnabledChanged(  
      DependencyObject attachingElement,  
      DependencyPropertyChangedEventArgs e)  
    {  
      if (!(attachingElement is System.Windows.Controls.ComboBox comboBox  
        && comboBox.IsEditable))  
      {  
        return;  
      }  
      if (!(bool)e.NewValue)  
      {  
        ComboBox.DisableAutocompleteFilter(comboBox);  
        return;  
      }  
  
      if (!comboBox.IsLoaded)  
      {  
        comboBox.Loaded += ComboBox.EnableAutocompleteFilterOnComboBoxLoaded;  
        return;  
      }  
      ComboBox.EnableAutocompleteFilter(comboBox);  
    }  
    private static async void FilterOnTextInput(object sender, TextChangedEventArgs e)  
    {  
      await Application.Current.Dispatcher.InvokeAsync(  
        () =>  
        {  
          if (ComboBox.IsNavigationKeyPressed)  
          {  
            return;  
          }  
          var textBox = sender as TextBox;  
          int textBoxSelectionStart = textBox.SelectionStart;  
          ComboBox.TextBoxSelectionStartMap[textBox] = textBoxSelectionStart;  
  
          string changedTextOnAutocomplete = textBox.Text.Substring(0, textBoxSelectionStart);  
          if (ComboBox.TextBoxComboBoxMap.TryGetValue(  
            textBox,  
            out System.Windows.Controls.ComboBox comboBox))  
          {  
            comboBox.Items.Filter = item => item.ToString().StartsWith(  
              changedTextOnAutocomplete,  
              StringComparison.OrdinalIgnoreCase);  
          }  
        },  
        DispatcherPriority.Background);  
    }  
    private static async void HandleKeyDownWhileFiltering(object sender, KeyEventArgs e)  
    {  
      var comboBox = sender as System.Windows.Controls.ComboBox;  
      if (!ComboBox.ComboBoxTextBoxMap.TryGetValue(comboBox, out TextBox textBox))  
      {  
        return;  
      }  
      switch (e.Key)  
      {  
        case Key.Down  
          when comboBox.Items.CurrentPosition < comboBox.Items.Count - 1  
               && comboBox.Items.MoveCurrentToNext():  
        case Key.Up  
          when comboBox.Items.CurrentPosition > 0  
               && comboBox.Items.MoveCurrentToPrevious():  
          {  
            ComboBox.IsNavigationKeyPressed = true;  
            await Application.Current.Dispatcher.InvokeAsync(  
              () =>  
              {  
                ComboBox.SelectCurrentItem(textBox, comboBox);  
                ComboBox.IsNavigationKeyPressed = false;  
              },  
              DispatcherPriority.ContextIdle);  
            break;  
          }  
      }  
    }  
    private static void SelectCurrentItem(TextBox textBox, System.Windows.Controls.ComboBox comboBox)  
    {  
      comboBox.SelectedItem = comboBox.Items.CurrentItem;  
      if (ComboBox.TextBoxSelectionStartMap.TryGetValue(textBox, out int selectionStart))  
      {  
        textBox.SelectionStart = selectionStart;  
      }  
    }  
    private static void EnableAutocompleteFilterOnComboBoxLoaded(object sender, RoutedEventArgs e)  
    {  
      var comboBox = sender as System.Windows.Controls.ComboBox;  
      ComboBox.EnableAutocompleteFilter(comboBox);  
    }  
  
    private static void EnableAutocompleteFilter(System.Windows.Controls.ComboBox comboBox)  
    {  
      if (comboBox.TryFindVisualChildElement(out TextBox editTextBox))  
      {  
        ComboBox.TextBoxComboBoxMap.Add(editTextBox, comboBox);  
        ComboBox.ComboBoxTextBoxMap.Add(comboBox, editTextBox);  
        editTextBox.TextChanged += ComboBox.FilterOnTextInput;  
  
        comboBox.AddHandler(UIElement.PreviewKeyDownEvent, new KeyEventHandler(HandleKeyDownWhileFiltering), true);  
      }  
    }  
    private static void DisableAutocompleteFilter(System.Windows.Controls.ComboBox comboBox)  
    {  
      if (comboBox.TryFindVisualChildElement(out TextBox editTextBox))  
      {  
        ComboBox.TextBoxComboBoxMap.Remove(editTextBox);  
        editTextBox.TextChanged -= ComboBox.FilterOnTextInput;  
      }  
    }  
  }  
  public static class Extensions  
  {  
    public static bool TryFindVisualChildElement<TChild>(this DependencyObject parent, out TChild resultElement)  
      where TChild : DependencyObject  
    {  
      resultElement = null;  
  
      if (parent is Popup popup)  
      {  
        parent = popup.Child;  
        if (parent == null)  
        {  
          return false;  
        }  
      }  
      for (var childIndex = 0; childIndex < VisualTreeHelper.GetChildrenCount(parent); childIndex++)  
      {  
        DependencyObject childElement = VisualTreeHelper.GetChild(parent, childIndex);  
        if (childElement is TChild child)  
        {  
          resultElement = child;  
          return true;  
        }  
  
        if (childElement.TryFindVisualChildElement(out resultElement))  
        {  
          return true;  
        }  
      }  
      return false;  
    }  
  }  

The result:

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