[英]How to color items in listBox in different colors? getting exception : Items collection cannot be modified when the DataSource property is set
在 listBox1 属性的设计器中，我将 DrawMode 设置为 OwnerDrawFixed
然后添加这个 class 用于着色：
public class MyListBoxItem
{
public MyListBoxItem(Color c, string m)
{
ItemColor = c;
Message = m;
}
public Color ItemColor { get; set; }
public string Message { get; set; }
}
并添加了 DrawItem 事件：
private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{
MyListBoxItem item = listBox1.Items[e.Index] as MyListBoxItem; // Get the current item and cast it to MyListBoxItem
if (item != null)
{
e.Graphics.DrawString( // Draw the appropriate text in the ListBox
item.Message, // The message linked to the item
listBox1.Font, // Take the font from the listbox
new SolidBrush(item.ItemColor), // Set the color
0, // X pixel coordinate
e.Index * listBox1.ItemHeight // Y pixel coordinate. Multiply the index by the ItemHeight defined in the listbox.
);
}
else
{
// The item isn't a MyListBoxItem, do something about it
}
}
然后我试图添加一些项目只是为了在构造函数中进行测试：每个项目都应该是另一种颜色：
listBox1.Items.Add(new MyListBoxItem(Colors.Green, "Validated data successfully"));
listBox1.Items.Add(new MyListBoxItem(Colors.Red, "Failed to validate data"));
但在第一个 listBox1.Items.Add 行上出现异常：
System.ArgumentException：“设置 DataSource 属性后无法修改项目集合。”
这是完整的代码：
using Newtonsoft.Json;
using Ookii.Dialogs.WinForms;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using static System.Windows.Forms.VisualStyles.VisualStyleElement;
using static System.Windows.Forms.VisualStyles.VisualStyleElement.ProgressBar;
using static System.Windows.Forms.VisualStyles.VisualStyleElement.Window;
namespace Image_Crop
{
public partial class Form1 : Form
{
Rectangle rect;
int pixelsCounter = 0;
Color SelectedColor = Color.LightGreen;
List<DrawingRectangle> DrawingRects = new List<DrawingRectangle>();
Bitmap rectImage;
int saveRectanglesCounter = 1;
bool drawBorder = true;
bool clearRectangles = true;
bool saveRectangles = true;
string rectangleName;
Dictionary<string, string> FileList = new Dictionary<string, string>();
string selectedPath;
int x, y;
private bool crop = false;
public Form1()
{
InitializeComponent();
textBox1.Text = Properties.Settings.Default.ImageToCropFolder;
textBox2.Text = Properties.Settings.Default.CroppedImagesFolder;
selectedPath = textBox2.Text;
if (textBox1.Text != "")
{
Bitmap bmp = new Bitmap(Image.FromFile(textBox1.Text),
pictureBox2.Width, pictureBox2.Height);
pictureBox2.Image = bmp;
}
checkBoxDrawBorder.Checked = true;
checkBoxClearRectangles.Checked = true;
checkBoxSaveRectangles.Checked = true;
if (selectedPath != "" && selectedPath != null)
{
if (System.IO.File.Exists(Path.Combine(selectedPath, "rectangles.txt")))
{
string g = System.IO.File.ReadAllText(Path.Combine(selectedPath, "rectangles.txt"));
g = g.Remove(0, 32);
FileList = JsonConvert.DeserializeObject<Dictionary<string, string>>(g);
listBox1.DataSource = FileList.Keys.ToList();
label2.Text = listBox1.Items.Count.ToString();
listBox1.SelectedIndex = listBox1.Items.Count - 1;
}
else
{
label2.Text = "0";
}
}
else
{
label2.Text = "0";
}
if ((selectedPath != "" && selectedPath != null) && textBox1.Text != "")
{
crop = true;
}
else
{
crop = false;
}
listBox1.Items.Add(new MyListBoxItem(Color.Green, "Validated data successfully"));
listBox1.Items.Add(new MyListBoxItem(Color.Red, "Failed to validate data"));
}
public class DrawingRectangle
{
public Rectangle Rect => new Rectangle(Location, Size);
public Size Size { get; set; }
public Point Location { get; set; }
public Control Owner { get; set; }
public Point StartPosition { get; set; }
public Color DrawingcColor { get; set; } = Color.LightGreen;
public float PenSize { get; set; } = 3f;
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void pictureBox2_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button != MouseButtons.Left || crop == false) return;
x = 0;
y = 0;
if (pictureBox2.Image != null && selectedPath != null)
{
if ((x >= 0 && x <= pictureBox2.Image.Size.Width) && (y >= 0 && y <= pictureBox2.Image.Size.Height))
{
DrawingRects.Add(new DrawingRectangle()
{
Location = e.Location,
Size = Size.Empty,
StartPosition = e.Location,
Owner = (Control)sender,
DrawingcColor = SelectedColor
});
}
}
}
private void pictureBox2_MouseMove(object sender, MouseEventArgs e)
{
int X = e.X;
int Y = e.Y;
if (e.Button != MouseButtons.Left || crop == false) return;
if ((X >= 0 && X <= pictureBox2.Width) && (Y >= 0 && Y <= pictureBox2.Height))
{
if (pictureBox2.Image != null && selectedPath != null && DrawingRects.Count > 0)
{
if ((x >= 0 && x <= pictureBox2.Image.Size.Width) && (y >= 0 && y <= pictureBox2.Image.Size.Height))
{
x = e.X;
y = e.Y;
var dr = DrawingRects[DrawingRects.Count - 1];
if (e.Y < dr.StartPosition.Y) { dr.Location = new Point(dr.Rect.Location.X, e.Y); }
if (e.X < dr.StartPosition.X) { dr.Location = new Point(e.X, dr.Rect.Location.Y); }
dr.Size = new Size(Math.Abs(dr.StartPosition.X - e.X), Math.Abs(dr.StartPosition.Y - e.Y));
pictureBox2.Invalidate();
}
}
}
}
int count = 0;
private void pictureBox2_MouseUp(object sender, MouseEventArgs e)
{
if (e.Button != MouseButtons.Left || crop == false) return;
if (DrawingRects.Count > 0 && pictureBox2.Image != null && selectedPath != "")
{
if ((x >= 0 && x <= pictureBox2.Image.Size.Width) && (y >= 0 && y <= pictureBox2.Image.Size.Height))
{
var dr = DrawingRects.Last();
if (dr.Rect.Width > 0 && dr.Rect.Height > 0)
{
rectImage = cropAtRect((Bitmap)pictureBox2.Image, dr.Rect);
if (saveRectangles)
{
count++;
rectangleName = GetNextName(Path.Combine(selectedPath, "Rectangle"), ".bmp");
FileList.Add($"{dr.Location}, {dr.Size}", rectangleName);
string json = JsonConvert.SerializeObject(
FileList,
Formatting.Indented
);
using (StreamWriter sw = new StreamWriter(Path.Combine(selectedPath, "rectangles.txt"), false))
{
sw.WriteLine("Total number of rectangles: " + count + Environment.NewLine);
sw.Write(json);
sw.Close();
}
rectImage.Save(rectangleName);
saveRectanglesCounter++;
}
else
{
var stream = ToMemoryStream(rectImage);
var image = System.Drawing.Image.FromStream(stream);
pictureBox1.Image = image;
}
pixelsCounter = rect.Width * rect.Height;
pictureBox1.Invalidate();
listBox1.DataSource = FileList.Keys.ToList();
listBox1.SelectedIndex = listBox1.Items.Count - 1;
pictureBox2.Focus();
Graphics g = Graphics.FromImage(this.pictureBox1.Image);
g.Clear(this.pictureBox1.BackColor);
}
}
else
{
if (clearRectangles)
{
DrawingRects.Clear();
pictureBox2.Invalidate();
}
x = 0;
y = 0;
}
}
}
public class MyListBoxItem
{
public MyListBoxItem(Color c, string m)
{
ItemColor = c;
Message = m;
}
public Color ItemColor { get; set; }
public string Message { get; set; }
}
public MemoryStream ToMemoryStream(Bitmap b)
{
MemoryStream ms = new MemoryStream();
b.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
return ms;
}
string GetNextName(string baseName, string extension)
{
int counter = 1;
string nextName = baseName + counter + extension;
while (System.IO.File.Exists(nextName))
{
counter++;
nextName = baseName + counter + extension;
}
return nextName;
}
private void pictureBox2_Paint(object sender, PaintEventArgs e)
{
if (drawBorder)
{
ControlPaint.DrawBorder(e.Graphics, pictureBox2.ClientRectangle, Color.Red, ButtonBorderStyle.Solid);
}
if (pictureBox2.Image != null && selectedPath != null && DrawingRects.Count > 0)
{
DrawShapes(e.Graphics);
}
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
if (drawBorder)
{
ControlPaint.DrawBorder(e.Graphics, pictureBox1.ClientRectangle, Color.Red, ButtonBorderStyle.Solid);
}
if (rectImage != null && DrawingRects.Count > 0)
{
var dr = DrawingRects.Last();
e.Graphics.DrawImage(rectImage, dr.Rect);
if (clearRectangles)
{
DrawingRects.Clear();
pictureBox2.Invalidate();
}
}
}
private void DrawShapes(Graphics g)
{
if (DrawingRects.Count == 0) return;
g.SmoothingMode = SmoothingMode.AntiAlias;
foreach (var dr in DrawingRects)
{
if (dr.Rect.Width > 0 && dr.Rect.Height > 0)
{
using (Pen pen = new Pen(dr.DrawingcColor, dr.PenSize))
{
g.DrawRectangle(pen, dr.Rect);
};
}
}
}
public Bitmap cropAtRect(Bitmap b, Rectangle r)
{
Bitmap nb = new Bitmap(r.Width, r.Height);
using (Graphics g = Graphics.FromImage(nb))
{
g.DrawImage(b, -r.X, -r.Y);
return nb;
}
}
private void checkBoxDrawBorder_CheckedChanged(object sender, EventArgs e)
{
if (checkBoxDrawBorder.Checked)
{
drawBorder = true;
}
else
{
drawBorder = false;
}
pictureBox1.Invalidate();
pictureBox2.Invalidate();
}
private void checkBoxClearRectangles_CheckedChanged(object sender, EventArgs e)
{
if (checkBoxClearRectangles.Checked)
{
clearRectangles = true;
}
else
{
clearRectangles = false;
}
pictureBox2.Invalidate();
}
private void checkBoxSaveRectangles_CheckedChanged(object sender, EventArgs e)
{
if(checkBoxSaveRectangles.Checked)
{
saveRectangles = true;
}
else
{
saveRectangles = false;
}
}
private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
var item = ((ListBox)sender).SelectedItem;
var val = FileList[(string)item];
if (File.Exists(val))
{
pictureBox1.Image = System.Drawing.Image.FromFile(val);
}
}
private void button1_Click(object sender, EventArgs e)
{
VistaOpenFileDialog dialog = new VistaOpenFileDialog();
{
dialog.Filter = "Images (*.jpg, *.bmp, *.gif)|*.jpg;*.bmp;*.gif";
};
if (dialog.ShowDialog() == DialogResult.OK)
{
textBox1.Text = dialog.FileName;
Properties.Settings.Default.ImageToCropFolder = dialog.FileName;
Properties.Settings.Default.Save();
Bitmap bmp = new Bitmap(Image.FromFile(dialog.FileName),
pictureBox2.Width, pictureBox2.Height);
pictureBox2.Image = bmp;
if(textBox1.Text != "" && textBox2.Text != "")
{
crop = true;
}
}
}
private void listBox1_DrawItem(object sender, DrawItemEventArgs e)
{
MyListBoxItem item = listBox1.Items[e.Index] as MyListBoxItem; // Get the current item and cast it to MyListBoxItem
if (item != null)
{
e.Graphics.DrawString( // Draw the appropriate text in the ListBox
item.Message, // The message linked to the item
listBox1.Font, // Take the font from the listbox
new SolidBrush(item.ItemColor), // Set the color
0, // X pixel coordinate
e.Index * listBox1.ItemHeight // Y pixel coordinate. Multiply the index by the ItemHeight defined in the listbox.
);
}
else
{
// The item isn't a MyListBoxItem, do something about it
}
}
private void button2_Click(object sender, EventArgs e)
{
VistaFolderBrowserDialog dialog = new VistaFolderBrowserDialog();
if (dialog.ShowDialog() == DialogResult.OK)
{
textBox2.Text = dialog.SelectedPath;
selectedPath = dialog.SelectedPath;
Properties.Settings.Default.CroppedImagesFolder = selectedPath;
Properties.Settings.Default.Save();
if (textBox1.Text != "" && textBox2.Text != "")
{
crop = true;
}
}
}
}
}
您的问题是如何在不同的 colors 中为列表框中的项目着色？ 可能被视为XY 问题的“Y”是当您尝试内联添加项目时出现异常。 仔细阅读您的代码后，会在您的DataSource和 Json 序列化和反序列化中一致地使用MyListBoxItem类型，然后在您希望内联添加项目时附加数据源，这会产生很大的不同。
数据源
BindingList<MyListBoxItem> MyItems { get; } = new BindingList<MyListBoxItem>();
磁盘文件中 Json 序列化形式的 MyItems 示例
[
{
"ItemColor": "Blue",
"Message": "Blue Item"
},
{
"ItemColor": "Green",
"Message": "Green Item"
},
{
"ItemColor": "Red",
"Message": "Red Item"
}
]
在哪里：
public class MyListBoxItem
{
public Color ItemColor { get; set; }
public string Message { get; set; }
}
listBox1绘图代码的主窗体初始化
public partial class MainForm : Form
{
public MainForm() => InitializeComponent();
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
listBox1.DisplayMember = nameof(MyListBoxItem.Message);
listBox1.DataSource = MyItems;
listBox1.DrawItem += onDrawItem;
listBox1.DrawMode = DrawMode.OwnerDrawFixed;
listBox1.SelectedIndexChanged += (sender, e) => listBox1.Refresh();
// Tests
buttonTest.Click += onButtonTest;
buttonReadJson.Click += onButtonReadJson;
}
private void onDrawItem(object sender, DrawItemEventArgs e)
{
if((e.Index == -1) || (e.Index >= MyItems.Count))
{
e.DrawBackground();
}
else
{
var myItem = MyItems[e.Index];
if (listBox1.SelectedItems.Contains(myItem))
{
using (var backgroundBrush = new SolidBrush(myItem.ItemColor))
{
e.Graphics.FillRectangle(backgroundBrush, e.Bounds);
}
using (var textBrush = new SolidBrush(Color.White))
{
e.Graphics.DrawString(myItem.Message, listBox1.Font, textBrush, e.Bounds);
}
}
else
{
using (var backgroundBrush = new SolidBrush(SystemColors.Window))
{
e.Graphics.FillRectangle(backgroundBrush, e.Bounds);
}
using (var textBrush = new SolidBrush(myItem.ItemColor))
{
e.Graphics.DrawString(myItem.Message, listBox1.Font, textBrush, e.Bounds);
}
}
}
}
BindingList<MyListBoxItem> MyItems { get; } = new BindingList<MyListBoxItem>();
.
.
.
}
添加项目的示例
private void onButtonTest(object sender, EventArgs e)
{
MyItems.Clear();
MyItems.Add(new MyListBoxItem
{
Message = "Validated data successfully",
ItemColor = Color.Green,
});
MyItems.Add(new MyListBoxItem
{
Message = "Failed to validate data",
ItemColor = Color.Red,
});
}
反序列化文件示例
private void onButtonReadJson(object sender, EventArgs e)
{
MyItems.Clear();
foreach (
var myItem
in JsonConvert.DeserializeObject<List<MyListBoxItem>>(mockFileContents))
{
MyItems.Add(myItem);
}
}
const string mockFileContents =
@"[
{
""ItemColor"": ""Blue"",
""Message"": ""Blue Item""
},
{
""ItemColor"": ""Green"",
""Message"": ""Green Item""
},
{
""ItemColor"": ""Red"",
""Message"": ""Red Item""
}
]";
列表框错误：设置了DataSource属性时，无法修改项目集合
[英]listbox error: Items collection cannot be modified when the DataSource property is set
例外：设置DataSource属性时，无法修改项集合
[英]Exception : Items collection cannot be modified when the DataSource property is set
C＃ListBox：设置DataSource属性时，无法修改Items集合
[英]C# ListBox : Items collection cannot be modified when the DataSource property is set
在c＃中设置DataSource属性时，无法修改项目集合
[英]Items collection cannot be modified when the DataSource property is set in c#
设置DataSource属性时，无法修改c＃项目集合
[英]c# Items collection cannot be modified when the DataSource property is set
设置DataSource属性后，将无法修改项目集合。 C＃
[英]Items collection cannot be modified when the DataSource property is set. c#
System.ArgumentException：“设置 DataSource 属性时无法修改项目集合。” C# Windows Forms
[英]System.ArgumentException: 'Items collection cannot be modified when the DataSource property is set.' C# Windows Forms
错误：其他信息：设置DataSource属性时，不能修改项目集合
[英]ERROR: Additional information: Items collection cannot be modified when the DataSource property is set
System.ArgumentException：设置DataSource属性时，不能修改Items集合
[英]System.ArgumentException: Items collection cannot be modified when the DataSource property is set
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