private void treeView1_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
{
    this.tabControl1.TabPages.Clear();
    if (e.Node.Level == 0)
    {
        foreach (TreeNode node in this.treeView1.Nodes[0].Nodes)//this.treeView1.Nodes[0]是销售基础数据所在的节点，具体你再调整
            this.tabControl1.TabPages.Add(node.Text, node.Text);
        return;
    }             
    this.tabControl1.TabPages.Add(e.Node.Text, e.Node.Text, 0);
}

------解决方案--------------------
C# code
TreeNode currNode;//当前节点
List<TabPage> list;//保存所有的TabPages
private void Form1_Load(object sender, EventArgs e)
{
    //把所有的TabPages放在list中
    list = new List<TabPage>();
    foreach (TabPage page in this.tabControl1.TabPages)
        list.Add(page);
}        
private void treeView1_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
{
    currNode = e.Node;            
    this.tabControl1.TabPages.Clear();
    if (e.Node.Level == 0)//单击父节点，显示全部
    {
        this.tabControl1.TabPages.AddRange(list.ToArray());
        return;
    }
    //在list中找到对应的TabPage加到TabControl中
    TabPage p = list.Find(new Predicate<TabPage>(find));
    if(p != null) this.tabControl1.TabPages.Add(p);
}
bool find(TabPage page)
{
    return page.Text == currNode.Text;
}

------解决方案--------------------
当然，list.Find()用委托实现的话更替紧凑写
C# code
TreeNode currNode;
List<TabPage> list;
private void Form1_Load(object sender, EventArgs e)
{
    list = new List<TabPage>();
    foreach (TabPage page in this.tabControl1.TabPages)
        list.Add(page);
}        
private void treeView1_NodeMouseClick(object sender, TreeNodeMouseClickEventArgs e)
{
    currNode = e.Node;            
    this.tabControl1.TabPages.Clear();
    if (e.Node.Level == 0)
    {
        this.tabControl1.TabPages.AddRange(list.ToArray());
        return;
    }
    TabPage p = list.Find(new Predicate<TabPage>(delegate(TabPage pageTem)
    {
        return pageTem.Text == currNode.Text;
    }));
    if(p != null) this.tabControl1.TabPages.Add(p);
}