我明白，你有这样的结构

D
|-java
    |-Document
    |-Person
    |-Picture

你说 “删除文件夹的内容”。所以，我假设你需要保留文件夹
在这种情况下

public void EmptyFolder(string root, IEnumerable<string> subfolders)
{
    foreach(string folder in subfolders) 
    {
        string dirPath = Path.Combine(root, folder);

        foreach (string subdir in Directory.EnumerateDirectories(dirPath))
            Directory.Delete(subdir, true);

        foreach (string file in Directory.EnumerateFiles(dirPath))
            File.Delete(file);
    }
}

// (assuming check box text is the name of folder. Or you can use tag property to set real folder name there)
private IEnumerable<string> Getfolders()
{
    foreach(control c in this.Controls) // "this" being a form or control, or use specificControl.Controls
    {
        if (c is Checkbox check && check.Checked)
            yield return check.Text; 
        
    }
}

// USAGE

EmptyFolder(@"D:\java\", Getfolders());

注：从内存写入，未测试

实现目标的众多方法之一：
1.在当前窗体上创建一个选中的复选框数组。
1.遍历数组以基于Text构建文件夹名称。
1.删除整个文件夹，然后用一个空文件夹替换。
如果您还没有熟悉System.Linq扩展方法（如Where和Any），那么您可能需要熟悉一下。
[清除]按钮应仅在选中某些内容时启用。

制作一个复选框数组会很方便。它可以在你每次Clear时使用。同时，除非一个或多个复选框被选中，否则不应该启用[清除]按钮。

public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();

        // Make an array of the checkboxes to use throughout the app.
        _checkboxes = Controls.OfType<CheckBox>().ToArray();

        // This provides a way to make sure the Clear button is
        // only enabled when one or more checkboxes is marked.
        foreach (CheckBox checkBox in _checkboxes)
        {
            checkBox.CheckedChanged += onAnyCheckboxChanged;
        }

        // Attach the 'Click' handler to the button if you 
        // haven't already done this in the form Designer.
        buttonClear.Enabled = false;
        buttonClear.Click += onClickClear;
    }
    const string basePath = @"D:\java\";
    CheckBox[] _checkboxes;
    .
    .
    .
}

将Clear按钮设置为启用（或不启用）

在这里，我们对复选框状态的更改做出响应。

private void onAnyCheckboxChanged(object sender, EventArgs e)
{
    buttonClear.Enabled = _checkboxes.Any(_=>_.Checked);
}

执行清除

使用复选框的Text构建子文件夹路径。如果选中该复选框，则删除整个文件夹，用新的空文件夹替换它。

private void onClickClear(object sender, EventArgs e)
{
    // Get the checkboxes that are selected.
    CheckBox[] selectedCheckBoxes = 
        _checkboxes.Where(_ => _.Checked).ToArray();
    foreach (CheckBox checkBox in selectedCheckBoxes)
    {
        // Build the folder path
        string folderPath = Path.Combine(basePath, checkBox.Text);
        // Can't delete if it doesn't exist.
        if (Directory.Exists(folderPath)) 
        {
            // Delete the directory and all its files and subfolders.
            Directory.Delete(path: folderPath, recursive: true);
        }
        // Replace deleted folder with new, empty one.
        Directory.CreateDirectory(path: folderPath);
    }
}