wpf对excel中的两列数据进行拟合，输出函数表达式和函数图像，并列出需要导入的nuget包和前端HTML代码

要在WPF应用程序中对Excel中的两列数据进行拟合，您可以使用Math.NET Numerics NuGet包来执行拟合。以下是所需的nuget包：

- MathNet.Numerics

以下是一个示例WPF应用程序，该应用程序允许用户选择一个Excel文件，然后选择要用于拟合的两列数据。应用程序将显示拟合函数的表达式和图形。

XAML代码：

<Window x:Class="ExcelDataFitting.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Excel Data Fitting" Height="350" Width="525">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="*"/>
        </Grid.ColumnDefinitions>
        <Label Grid.Row="0" Grid.Column="0" Content="Excel File:"/>
        <TextBox Grid.Row="0" Grid.Column="1" Width="200" Text="{Binding ExcelFilePath}" IsReadOnly="True"/>
        <Button Grid.Row="0" Grid.Column="2" Content="Browse" Margin="5" Command="{Binding BrowseCommand}"/>
        <Label Grid.Row="1" Grid.Column="0" Content="X Data Column:"/>
        <ComboBox Grid.Row="1" Grid.Column="1" Width="200" ItemsSource="{Binding ExcelColumns}" SelectedItem="{Binding XDataColumn}"/>
        <Label Grid.Row="2" Grid.Column="0" Content="Y Data Column:"/>
        <ComboBox Grid.Row="2" Grid.Column="1" Width="200" ItemsSource="{Binding ExcelColumns}" SelectedItem="{Binding YDataColumn}"/>
        <Grid Grid.Row="3" Grid.ColumnSpan="3">
            <Grid.RowDefinitions>
                <RowDefinition Height="Auto"/>
                <RowDefinition Height="*"/>
            </Grid.RowDefinitions>
            <TextBlock Grid.Row="0" Text="{Binding FunctionExpression}" Margin="5"/>
            <Image Grid.Row="1" Source="{Binding FunctionGraph}" Stretch="Uniform" Margin="5"/>
        </Grid>
    </Grid>
</Window>

ViewModel代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.IO;
using System.Linq;
using System.Windows;
using System.Windows.Input;
using MathNet.Numerics;
using MathNet.Numerics.Fitting;
using MathNet.Numerics.LinearAlgebra;

namespace ExcelDataFitting
{
    public class MainWindowViewModel : INotifyPropertyChanged
    {
        private string _excelFilePath;
        private List<string> _excelColumns;
        private string _xDataColumn;
        private string _yDataColumn;
        private string _functionExpression;
        private BitmapImage _functionGraph;

        public string ExcelFilePath
        {
            get { return _excelFilePath; }
            set
            {
                _excelFilePath = value;
                OnPropertyChanged(nameof(ExcelFilePath));
            }
        }

        public List<string> ExcelColumns
        {
            get { return _excelColumns; }
            set
            {
                _excelColumns = value;
                OnPropertyChanged(nameof(ExcelColumns));
            }
        }

        public string XDataColumn
        {
            get { return _xDataColumn; }
            set
            {
                _xDataColumn = value;
                OnPropertyChanged(nameof(XDataColumn));
                UpdateFunction();
            }
        }

        public string YDataColumn
        {
            get { return _yDataColumn; }
            set
            {
                _yDataColumn = value;
                OnPropertyChanged(nameof(YDataColumn));
                UpdateFunction();
            }
        }

        public string FunctionExpression
        {
            get { return _functionExpression; }
            set
            {
                _functionExpression = value;
                OnPropertyChanged(nameof(FunctionExpression));
            }
        }

        public BitmapImage FunctionGraph
        {
            get { return _functionGraph; }
            set
            {
                _functionGraph = value;
                OnPropertyChanged(nameof(FunctionGraph));
            }
        }

        public ICommand BrowseCommand { get; }

        public MainWindowViewModel()
        {
            BrowseCommand = new RelayCommand(Browse);
        }

        private void Browse()
        {
            Microsoft.Win32.OpenFileDialog dlg = new Microsoft.Win32.OpenFileDialog();
            dlg.DefaultExt = ".xlsx";
            dlg.Filter = "Excel Files|*.xls;*.xlsx;*.xlsm";
            bool? result = dlg.ShowDialog();
            if (result == true)
            {
                ExcelFilePath = dlg.FileName;
                ExcelColumns = GetExcelColumns(dlg.FileName);
                XDataColumn = ExcelColumns.FirstOrDefault();
                YDataColumn = ExcelColumns.FirstOrDefault();
            }
        }

        private List<string> GetExcelColumns(string fileName)
        {
            List<string> columns = new List<string>();
            try
            {
                using (var stream = File.Open(fileName, FileMode.Open, FileAccess.Read))
                {
                    using (var reader = ExcelReaderFactory.CreateReader(stream))
                    {
                        var dataSet = reader.AsDataSet();
                        foreach (DataTable table in dataSet.Tables)
                        {
                            foreach (DataColumn column in table.Columns)
                            {
                                columns.Add(column.ColumnName);
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error loading Excel file: " + ex.Message);
            }
            return columns;
        }

        private void UpdateFunction()
        {
            if (string.IsNullOrEmpty(ExcelFilePath) || string.IsNullOrEmpty(XDataColumn) || string.IsNullOrEmpty(YDataColumn))
            {
                FunctionExpression = null;
                FunctionGraph = null;
                return;
            }

            try
            {
                using (var stream = File.Open(ExcelFilePath, FileMode.Open, FileAccess.Read))
                {
                    using (var reader = ExcelReaderFactory.CreateReader(stream))
                    {
                        var dataSet = reader.AsDataSet();
                        var dataTable = dataSet.Tables[0];
                        var xData = dataTable.AsEnumerable().Select(r => Convert.ToDouble(r[XDataColumn])).ToArray();
                        var yData = dataTable.AsEnumerable().Select(r => Convert.ToDouble(r[YDataColumn])).ToArray();
                        Tuple<double, double>[] points = new Tuple<double, double>[xData.Length];
                        for (int i = 0; i < xData.Length; i++)
                        {
                            points[i] = Tuple.Create(xData[i], yData[i]);
                        }
                        var coefficients = Fit.Polynomial(points, 2);
                        FunctionExpression = string.Format("{0:F4}x^2 + {1:F4}x + {2:F4}", coefficients[2], coefficients[1], coefficients[0]);
                        var xMin = xData.Min();
                        var xMax = xData.Max();
                        var xRange = xMax - xMin;
                        var xStep = xRange / 1000;
                        var xValues = Vector<double>.Build.Dense(1001, i => xMin + i * xStep);
                        var yValues = xValues.PointwiseMultiply(xValues).PointwiseMultiply(coefficients[2]).Add(xValues.PointwiseMultiply(coefficients[1])).Add(coefficients[0]);
                        var chart = new Chart(width: 800, height: 600)
                            .AddSeries(
                                name: "Function",
                                chartType: "line",
                                xValue: xValues.ToArray(),
                                yValues: yValues.ToArray())
                            .SetXAxis(title: XDataColumn)
                            .SetYAxis(title: YDataColumn);
                        using (var memoryStream = new MemoryStream())
                        {
                            chart.SaveImage(memoryStream, ChartImageFormat.Png);
                            var bitmapImage = new BitmapImage();
                            bitmapImage.BeginInit();
                            bitmapImage.StreamSource = new MemoryStream(memoryStream.ToArray());
                            bitmapImage.EndInit();
                            FunctionGraph = bitmapImage;
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Error fitting data: " + ex.Message);
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public class RelayCommand : ICommand
    {
        private readonly Action _execute;
        private readonly Func<bool> _canExecute;

        public RelayCommand(Action execute, Func<bool> canExecute = null)
        {
            if (execute == null)
                throw new ArgumentNullException(nameof(execute));

            _execute = execute;
            _canExecute = canExecute;
        }

        public bool CanExecute(object parameter)
        {
            return _canExecute == null || _canExecute();
        }

        public void Execute(object parameter)
        {
            _execute();
        }

        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }
    }
}

此应用程序使用MathNet Numerics执行一个二次拟合，您可以使用其他函数库来执行不同类型的拟合。最后，您需要将NuGet包的引用添加到WPF项目中，并在App.xaml.cs中设置启动窗口：

public partial class App : Application
{
    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);
        MainWindow mainWindow = new MainWindow();
        MainWindowViewModel viewModel = new MainWindowViewModel();
        mainWindow.DataContext = viewModel;
        mainWindow.Show();
    }
}

这样，您就可以拟合Excel中的数据并显示图形和函数表达式了。