我有一个 Windows 窗体（父窗体），它从文本框中获取一个值，然后打开子窗体，然后使用该值从目录中选择一个图像。当为特定值找到多个图像时，我修改了表单以显示几个按钮来导航（下一个和上一个）以显示不同的图像。首先打开父表单，输入一个值，然后使用 form.show() 显示子表单——一切都按预期工作。但是，如果在父表单中输入了另一个值（子表单仍然可以打开或退出（隐藏））并且单击“下一步”按钮，则单击事件中的代码将再次运行，因为列表中有许多图像（图片发现）。假设我在 List(imagesFound) 中有 3 个图像，并且我在调试模式下逐步执行代码，btnNext click 事件连续触发 3 次。这当然会运行 GetMultiImages 方法，该方法会导致显示图像的顺序全部完成。同样，第一次将值输入父表单时不会发生这种情况。我已确保在 GetImage 方法中清除了列表和其他变量。我被难住了……有什么想法吗？
表格1：
public partial class Form1 : Form
{
private string parcelID;
Form2 viewer = new Form2();
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
parcelID = txtParID.Text;
ShowViewer();
}
private void ShowViewer()
{
viewer.GetImage(parcelID);
if (viewer.NoImageFound == true)
{
viewer.Show();
viewer.Focus();
}
else if (viewer.NoImageFound == false)
{
viewer.Hide();
}
}
}
儿童表格：
public partial class Form2 : Form
{
public Button btnNext = new Button();
public Button btnPrev = new Button();
private List<string> imagesFound = new List<string>();
private string Path;
private string parcel;
private int increment;
private int maxNum;
public bool NoImageFound;
//multi image members
private string firstMultiItem;
private string selectMultiImage;
Image parMultiImage;
public Form2()
{
InitializeComponent();
}
public void GetImage(string ParcelID)
{
NoImageFound = true;
parcel = ParcelID;
increment = 0;
maxNum = 0;
firstMultiItem = null;
selectMultiImage = null;
parMultiImage = null;
imagesFound.Clear();
Path = "........\\Images\\";
try
{
if (!string.IsNullOrEmpty(parcel))
{
string parcelTrim = parcel.Substring(0, 6);
Path = Path + parcelTrim + "\\";
foreach (string s in Directory.GetFiles(Path, parcel + "_" + "*"))
{
string trimString = s.Replace(Path, "");
imagesFound.Add(trimString);
}
if ((imagesFound.Count == 0))
{
MessageBox.Show("No images found for ParcelID: " + parcel);
picBox.Image = null;
this.Text = "";
NoImageFound = false;
}
else
{
if (imagesFound.Count == 1)
{
string firstItem = imagesFound[0].ToString();
string selectImage = Path + firstItem;
Image parImage = Image.FromFile(selectImage);
//in order to access the picture box control you have to change it's
//access modifier (Modifier) from private to public. Defaults to private
picBox.Image = parImage;
picBox.SizeMode = PictureBoxSizeMode.StretchImage;
this.Text = parcel;
SingleForm();
}
else if (imagesFound.Count > 1)
{
firstMultiItem = imagesFound[0].ToString();
maxNum = imagesFound.Count;
selectMultiImage = Path + firstMultiItem;
parMultiImage = Image.FromFile(selectMultiImage);
picBox.Image = parMultiImage;
picBox.SizeMode = PictureBoxSizeMode.StretchImage;
this.Text = parcel;
MultiImageForm();
}
}
}
else
{
MessageBox.Show("No ParcelID");
}
}
catch (DirectoryNotFoundException)
{
string text = parcel;
MessageBox.Show("ParcelID: " + text + " could not be found. The directory may be missing.", "There's a problem locating the image.",
MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void SingleForm()
{
this.Height = 400;
btnNext.Visible = false;
btnPrev.Visible = false;
}
private void MultiImageForm()
{
//set form properties
this.Text = parcel;
this.Height = 432;
//set btnNext properties
btnNext.Location = new Point(307, 375);
btnNext.Size = new Size(75, 25);
btnNext.Font = new Font("Maiandra GD", 10, FontStyle.Bold);
btnNext.Text = ">>";
//add btnNext to form
this.Controls.Add(btnNext);
btnNext.Visible = true;
btnNext.Enabled = true;
//creating event handler for btnNext
btnNext.Click += new EventHandler(btnNext_Click);
//set btnPrev properties
btnPrev.Location = new Point(12, 375);
btnPrev.Size = new Size(75, 25);
btnPrev.Font = new Font("Maiandra GD", 10, FontStyle.Bold);
btnPrev.Text = "<<";
//add btnPrev to form
this.Controls.Add(btnPrev);
btnPrev.Visible = true;
btnPrev.Enabled = false;
//creating event handler for btnPrev
btnPrev.Click += new EventHandler(btnPrev_Click);
}
private void GetMultiImages()
{
try
{
firstMultiItem = imagesFound[increment].ToString();
selectMultiImage = Path + firstMultiItem;
parMultiImage = Image.FromFile(selectMultiImage);
picBox.Image = parMultiImage;
picBox.SizeMode = PictureBoxSizeMode.StretchImage;
}
catch (IndexOutOfRangeException)
{
MessageBox.Show("Index was out of range.");
}
}
private void btnNext_Click(object sender, System.EventArgs e)
{
if (increment != maxNum - 1)
{
increment++;
GetMultiImages();
}
EnableButtons();
}
private void btnPrev_Click(object sender, System.EventArgs e)
{
if (increment > 0)
{
increment--;
GetMultiImages();
}
EnableButtons();
}
private void EnableButtons()
{
if (increment == 0)
{
btnPrev.Enabled = false;
btnNext.Enabled = true;
}
else if (increment > 0 & increment != maxNum - 1)
{
btnPrev.Enabled = true;
btnNext.Enabled = true;
}
else if (increment == maxNum - 1)
{
btnPrev.Enabled = true;
btnNext.Enabled = false;
}
}
private void Form2_FormClosing(object sender, FormClosingEventArgs e)
{
//overriding closing event
this.Hide();
e.Cancel = true;
}
}