清除(重置)动态生成的图片框

Question

` private void getbtn_Click(object sender, EventArgs e)  // To generate Images
        {
            if (cmbDocType.SelectedIndex > 0)
            {

                if (con.State != ConnectionState.Open)
                    con.Open();
                string directory = System.IO.Directory.GetDirectoryRoot(System.IO.Directory.GetCurrentDirectory().ToString());
                string FileNamePath = directory + "MembersDocuments\\" + GlobalValues.Member_ID + "\\" + cmbDocType.Text;
                string[] list = Directory.GetFiles(FileNamePath);
                if (list.Length > 0)
                {
                    label1.Text = "";
                    PictureBox[] picturebox = new PictureBox[list.Length];
                    int y = 0;

                    for (int index = 0; index < picturebox.Length; index++)
                    {
                        picturebox[index] = new PictureBox();

                        if (x % 3 == 0)
                        {
                            y = y + 150; // 3 images per rows, first image will be at (20,150)
                            x = 0;
                        }
                        picturebox[index].Location = new Point(x * 230 + 20, y);
                        picturebox[index].Size = new Size(200, 150);
                        x++;

                        picturebox[index].Size = new Size(200, 100);
                        picturebox[index].Image = Image.FromFile(list[index]);
                        picturebox[index].SizeMode = PictureBoxSizeMode.StretchImage;

                        picturebox[index].Click += new EventHandler(picturebox_Click);

                        cmbDocType_SelectedIndexChanged(picturebox[index], e);
                        this.Controls.Add(picturebox[index]);

                    }

                }

                else
                {
                    label1.Text = "No Images to display";
                    label1.ForeColor = Color.Red;
                }

                con.Close();
            }
            else
            {
                MessageBox.Show("Please select the Document Type");
            }


        }
            `

谁能告诉我如何在新的调用中清除动态创建的pictureboxes中的先前图像(第一次调用的结果)。在进行新的调用时，以前的图像不应该是seen..in c#我有名为类型的组合框。比方说，如果我的组合框中有氨基酸，鸟。第一次呼叫时，将显示动物的图片，第二次选择组合框(即鸟类)时，将显示两种类型的图片。我需要一次显示单一类型的图片。在c#中，谢谢；

Answer 1

正如TaW在评论中所建议的：

private List<PictureBox> PBs = new List<PictureBox>();

private void getbtn_Click(object sender, EventArgs e)  // To generate Images
{
    if (cmbDocType.SelectedIndex > 0)
    {
        foreach(PictureBox pb in PBs)
        {
            pb.Dispose();
        }
        PBs.Clear();

        if (con.State != ConnectionState.Open)
            con.Open();
        string directory = System.IO.Directory.GetDirectoryRoot(System.IO.Directory.GetCurrentDirectory().ToString());
        string FileNamePath = directory + "MembersDocuments\\" + GlobalValues.Member_ID + "\\" + cmbDocType.Text;
        string[] list = Directory.GetFiles(FileNamePath);
        if (list.Length > 0)
        {
            label1.Text = "";
            PictureBox PB;
            int y = 0;

            for (int index = 0; index < list.Length; index++)
            {
                PB = new PictureBox();

                if (x % 3 == 0)
                {
                    y = y + 150; // 3 images per rows, first image will be at (20,150)
                    x = 0;
                }
                PB.Location = new Point(x * 230 + 20, y);
                PB.Size = new Size(200, 150);
                x++;

                PB.Size = new Size(200, 100);
                PB.Image = Image.FromFile(list[index]);
                PB.SizeMode = PictureBoxSizeMode.StretchImage;

                PB.Click += new EventHandler(picturebox_Click);
                PBs.Add(PB);
                this.Controls.Add(PB)
                cmbDocType_SelectedIndexChanged(PB, e);
            }
        }

        else
        {
            label1.Text = "No Images to display";
            label1.ForeColor = Color.Red;
        }

        con.Close();
    }
    else
    {
        MessageBox.Show("Please select the Document Type");
    }
}