我没有正确序列化窗体中的所有控件
我检查了fieldDataList是否包含所有控件，但在xml文件中只得到一个条目
是什么原因导致列表中的所有项都没有序列化到xml文件中？
序列化的代码：

using System;
using System.Collections.Generic;
using System.IO;
using System.Windows.Forms;
using System.Xml;
using System.Xml.Serialization;

public class FieldData
{
    public string ControlName { get; set; }
    public string Value { get; set; }
}

public class MainForm : Form
{
    private List<FieldData> fieldDataList;

    public MainForm()
    {
        // Initialize the list to store field data
        fieldDataList = new List<FieldData>();

        // Add controls to the form
        TextBox textBox1 = new TextBox();
        textBox1.Name = "textBox1";

        TextBox textBox2 = new TextBox();
        textBox2.Name = "textBox2";
        Button saveButton = new Button();
        saveButton.Text = "Save";
        saveButton.Click += SaveButton_Click;
        Button loadButton = new Button();
        loadButton.Text = "Load";
        loadButton.Click += LoadButton_Click;

        // Add controls to the form's controls collection
        Controls.Add(textBox1);
        Controls.Add(textBox2);
        Controls.Add(saveButton);
        Controls.Add(loadButton);
    }

    private void SaveButton_Click(object sender, EventArgs e)
    {
        // Collect field data from all controls on the form
        CollectFieldData(Controls[0]);

        // Save the field data to an XML file
        string filePath = "field_data.xml";
        SaveFieldDataToXml(filePath);

        MessageBox.Show("Field data saved to XML file: " + filePath);
    }

    private void LoadButton_Click(object sender, EventArgs e)
    {
        // Load field data from an XML file
        string filePath = "field_data.xml";
        LoadFieldDataFromXml(filePath);

        // Update the controls on the form with the loaded field data
        UpdateFormControls();

        MessageBox.Show("Field data loaded from XML file: " + filePath);
    }

    private void SaveFieldDataToXml(string filePath)
    {
        XmlSerializer serializer = new XmlSerializer(typeof(List<FieldData>));
        using (StreamWriter writer = new StreamWriter(filePath))
        {
            serializer.Serialize(writer, fieldDataList);
        }
    }

    private void LoadFieldDataFromXml(string filePath)
    {
        XmlSerializer serializer = new XmlSerializer(typeof(List<FieldData>));
        using (StreamReader reader = new StreamReader(filePath))
        {
            fieldDataList = (List<FieldData>)serializer.Deserialize(reader);
        }
    }
private void CollectFieldData(Control parentControl)
{
    foreach (Control control in parentControl.Controls)
    {
        if (control is TextBox textBox)
        {
            // Collect text box value
            FieldData fieldData = new FieldData();
            fieldData.ControlName = textBox.Name;
            fieldData.Value = textBox.Text;
            fieldDataList.Add(fieldData);
        }
        else if (control is NumericUpDown numericUpDown)
        {
            // Collect numeric up-down value
            FieldData fieldData = new FieldData();
            fieldData.ControlName = numericUpDown.Name;
            fieldData.Value = numericUpDown.Value.ToString();
            fieldDataList.Add(fieldData);
        }
        else if (control is CheckBox checkBox)
        {
            // Collect checkbox value
            FieldData fieldData = new FieldData();
            fieldData.ControlName = checkBox.Name;
            fieldData.Value = checkBox.Checked.ToString();
            fieldDataList.Add(fieldData);
        }
        else if (control.HasChildren)
        {
            // Recursively collect field data for child controls
            CollectFieldData(control);
        }
    }
}

private void UpdateFormControls(Control parentControl)
{
    foreach (Control control in parentControl.Controls)
    {
        if (control is TextBox textBox)
        {
            // Find the corresponding field data and update the text box value
            FieldData fieldData = fieldDataList.Find(data => data.ControlName == textBox.Name);
            if (fieldData != null)
            {
                textBox.Text = fieldData.Value;
            }
        }
        else if (control is NumericUpDown numericUpDown)
        {
            // Find the corresponding field data and update the numeric up-down value
            FieldData fieldData = fieldDataList.Find(data => data.ControlName == numericUpDown.Name);
            if (fieldData != null)
            {
                if (decimal.TryParse(fieldData.Value, out decimal value))
                {
                    numericUpDown.Value = value;
                }
            }
        }
        else if (control is CheckBox checkBox)
        {
            // Find the corresponding field data and update the checkbox value
            FieldData fieldData = fieldDataList.Find(data => data.ControlName == checkBox.Name);
            if (fieldData != null)
            {
                if (bool.TryParse(fieldData.Value, out bool value))
                {
                    checkBox.Checked = value;
                }
            }
        }
        else if (control.HasChildren)
        {
            // Recursively update child controls
            UpdateFormControls(control);
        }
    }
}

    public static void Main()
    {
        Application.Run(new MainForm());
    }
}

我得到的序列化文件的内容如下

<?xml version="1.0" encoding="utf-8"?><ArrayOfFieldData xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" />