I have a grid that I'm trying to remove an item in specific line. It's in a loop, then when it goes to the second line, it removes the item in second line and ALSO in the first line. How can I adjust to remove only the line that I want?
Note that what I'm trying to do is copy the first line to the second only solving the pow (b²), and in the third line I will copy the second line, but solve -4 * 5 (-4 * a).
This is the preview of what is happening.
This is my code to inflate these lines, to understand:
It enters first in the if(fields == null) because is pow, after that, goes to else:
for (int i = 0; i < qntLines; i )
{
string field = lines[i].Substring(0, lines[i].IndexOf('#'));
string operation = lines[i].Substring(lines[i].IndexOf('#') "#".Length);
CreateResultLine(field, operation, i, listTexts);
}
private void CreateResultLine(string field, string operation, int i, List<string> listTexts)
{
string[] fields = null;
List<string> texts = new List<string>();
string text = string.Empty;
dynamic textResult;
int count = new int();
if (field.Contains(','))
fields = field.Split(',', (char)StringSplitOptions.RemoveEmptyEntries);
if (fields == null)
{
text = listTexts[int.Parse(field)];
text = RemovePow(text);
texts.Add(text);
textResult = ExecuteOperation(texts, operation);
gridFrame.Children.RemoveAt(int.Parse(field) 1);
gridFrame.Children.Add(new Label() { Text = textResult.ToString(), HorizontalTextAlignment = TextAlignment.Center,
TextColor = Color.Blue, HorizontalOptions = LayoutOptions.Center }, int.Parse(field) 1, i);
}
else
{
foreach (var item in fields)
{
string noPow = string.Empty;
noPow = RemovePow(listTexts[int.Parse(item)]);
texts.Add(noPow);
count;
}
textResult = ExecuteOperation(texts, operation);
for (int i2 = int.Parse(fields[0]); i2 <= int.Parse(fields[1]);)
{
gridFrame.Children.RemoveAt(int.Parse(fields[0]));
i2;
}
gridFrame.Children.Add(new Label() { Text = textResult.ToString(), HorizontalTextAlignment = TextAlignment.Center,
TextColor = Color.Blue, HorizontalOptions = LayoutOptions.Center }, int.Parse(fields[0]) 1, i);
}
}
CodePudding user response：
A bit confused of what you're trying to achieve, but here's a sugestion.
I recommend going for a MVVM pattern. Manipulating UI in code is not the best idea.
<ContentPage.BindingContext>
<local: MainViewModel />
</ContentPage.BindingContext>
<ContentPage.Content>
<ListView ItemSource={Binding ListOfItems}>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<Label Text={Binding .}/>
<ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</ContentPage.Content>
MainViewModel.cs
public class MainViewModel : INotifyPropertyChanged
{
public ObservableCollection<string> ListOfItems {get;set;} = new ObservableCollection<string>();
public void DeleteAnItem(string s)
{
ListOfItems.Remove(s);
}
public void AddItem(string s)
{
ListOfItems.Add(s);
}
public void RemoveAtIndex(int i)
{
ListOfItems.RemoveAt(i);
}
#region TheRestOfPropertyChanged
...
#endregion
}
Every change you do to the list will be visibile in your UI.
CodePudding user response：
Here is a complete example of working with the cells of a grid.
The concept is that you first create all the cells. Here, I use a Label in each grid cell. To make it easier to understand, I set each cell's text to the "CellNumber" that I assign to it. Once you understand what is going on, just put an empty string "" as the initial value.
To make it easy to find the cells, there is a Dictionary containing them. CellNumber(row, column) gives the key to that dictionary, to find the corresponding cell.
Calculate button makes some changes to cells, so you can see how to do that.
I recommend NOT adding or removing cells (Children of Grid) once this is initialized. Instead, SHOW or HIDE a cell. Here, you do this by changing the Text of a Label. For other types of Views, you might change View.IsVisible to true or false.
MainPage.xaml:
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="ManipulateGridChildren.MainPage">
<Grid x:Name="Formulas" BackgroundColor="#A0A0A0"
RowSpacing="2" ColumnSpacing="2" Padding="2"
ColumnDefinitions="*,*,*,*,*,*,*,*"
RowDefinitions="40,40,40,Auto">
<Button Grid.Row="3" Text="Calc" Command="{Binding CalcCommand}" />
</Grid>
</ContentPage>
MainPage.xaml.cs:
using System.Collections.Generic;
using Xamarin.Forms;
namespace ManipulateGridChildren
{
public partial class MainPage : ContentPage
{
const int NRows = 3;
static int NColumns = 8;
const int MaxColumns = 100;
private Dictionary<int, Label> cells = new Dictionary<int, Label>();
public MainPage()
{
InitializeComponent();
AddCells();
CalcCommand = new Command(Calculate);
BindingContext = this;
}
public Command CalcCommand { get; set; }
private void Calculate()
{
SetCellText(0, 0, "A");
SetCellText(0, 2, "B");
SetCellText(1, 0, "C");
SetCellText(2, 3, "D");
SetCellBackground(2, 3, Color.Pink)
}
private void SetCellText(int row, int column, string text)
{
cells[CellNumber(row, column)].Text = text;
}
private void SetCellBackground(int row, int column, Color color)
{
cells[CellNumber(row, column)].BackgroundColor = color;
}
private void AddCells()
{
// Grid rows and columns are numbered from "0".
for (int row = 0; row < NRows; row ) {
for (int column = 0; column < NColumns; column ) {
var cell = AddCell(row, column);
cells[CellNumber(row, column)] = cell;
}
}
// Add "frames" around some rows.
// AFTER adding the cells, so drawn on top.
AddFrame(0, 1, 0, NColumns);
AddFrame(1, 2, 0, NColumns);
}
private Label AddCell(int row, int column)
{
var cell = new Label();
// For debugging - show where each cell is.
// Once you understand, change this to an empty string.
cell.Text = $"{CellNumber(row, column)}";
cell.BackgroundColor = Color.White;
cell.HorizontalTextAlignment = TextAlignment.Center;
cell.VerticalTextAlignment = TextAlignment.Center;
Formulas.Children.Add(cell, column, row);
return cell;
}
// Assign unique number to each cell.
private int CellNumber(int row, int column)
{
return row * MaxColumns column;
}
private void AddFrame(int row, int rowSpan, int column, int columnSpan)
{
var rect = new Xamarin.Forms.Shapes.Rectangle {
Stroke = new SolidColorBrush(Color.Black),
StrokeThickness = 2
};
Formulas.Children.Add(rect, column, column columnSpan, row, row rowSpan);
}
}
}