在创建某些应用程序时，首选具有多行内容的列表框。由于列表框没有这样的功能，因此需要创建自定义控件。对于这种情况，我正在开发一个编译器应用程序，用户可以将导入和导出 C# 预制件加载到程序中以操作数据。要查看此编译器的实际运行情况，您可以在此处查看我之前的帖子。对于这种情况，我希望将任何错误的调试日志输出到列表框中。由于一些错误包含多行，其中一些相当长，我阅读并生成了一个文本框项目的列表框。
可以在pastebin上找到它的最新副本。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace DataStripper
{
public partial class MultiLineListView : System.Windows.Forms.ListBox
{
public MultiLineListView()
{
//InitializeComponent();
this.DrawMode = DrawMode.OwnerDrawVariable;
this.ScrollAlwaysVisible = true;
tbox.Hide();
tbox.mllb = this;
Controls.Add(tbox);
}
protected override void OnMeasureItem(MeasureItemEventArgs e)
{
if (Site != null)
return;
if (e.Index > -1)
{
string s = Items[e.Index].ToString();
float best = 0;
foreach (string line in s.Split(new string[] { Environment.NewLine }, StringSplitOptions.None))
{
float chk = e.Graphics.MeasureString(line, Font, Width).Width;
if (chk > best)
best = chk;
}
SizeF sf = e.Graphics.MeasureString(s, Font, Width);
int htex = 1;//(e.Index == 0) ? 15 : 10;
e.ItemHeight = (int)(sf.Height*Items.Count) + htex;
e.ItemWidth = (int)best;
/*NTextBox i = (NTextBox)Items[e.Index];
e.ItemHeight = i.Height;
e.ItemWidth = i.Width;*/
}
}
protected override void OnDrawItem(DrawItemEventArgs e)
{
if (Site != null)
return;
if (e.Index > -1)
{
string s = Items[e.Index].ToString();
if ((e.State & DrawItemState.Focus) == 0)
{
e.Graphics.FillRectangle(new SolidBrush(SystemColors.Window), e.Bounds);
e.Graphics.DrawString(s, Font, new SolidBrush(SystemColors.WindowText),
e.Bounds);
e.Graphics.DrawRectangle(new Pen(SystemColors.Highlight), e.Bounds);
}
else
{
e.Graphics.FillRectangle(new SolidBrush(SystemColors.Highlight), e.Bounds);
e.Graphics.DrawString(s, Font, new SolidBrush(SystemColors.HighlightText),
e.Bounds);
}
}
}
protected override void OnMouseUp(System.Windows.Forms.MouseEventArgs e)
{
int index = IndexFromPoint(e.X, e.Y);
if (index != ListBox.NoMatches &&
index != 65535)
{
/*if (e.Button == MouseButtons.Right)
{
SelectedIndex = index;
Focus();
//tbox.index = index;
}*/
/*if (e.Button == MouseButtons.Right)
{
string s = Items[index].ToString();
Rectangle rect = GetItemRectangle(index);
tbox.Location = new Point(rect.X, rect.Y);
tbox.Size = new Size(rect.Width, rect.Height);
tbox.Text = s;
tbox.index = index;
tbox.SelectAll();
tbox.Show();
tbox.Focus();
}*/
}
base.OnMouseUp(e);
}
NTextBox tbox = new NTextBox();
class NTextBox : TextBox
{
public MultiLineListView mllb;
public int index = -1;
bool errshown = false;
bool brementer = false;
public NTextBox()
{
Multiline = true;
MaxLength = 2147483647;
MaximumSize = new System.Drawing.Size(0, 0);
WordWrap = false;
ScrollBars = ScrollBars.Both;
AcceptsReturn = true;
AcceptsTab = true;
}
protected override void OnKeyUp(KeyEventArgs e)
{
if (brementer)
{
Text = "";
brementer = false;
}
base.OnKeyUp(e);
}
protected override void OnKeyPress(KeyPressEventArgs e)
{
base.OnKeyPress(e);
}
protected override void OnLostFocus(System.EventArgs e)
{
if (Text.Trim() == "")
{
if (!errshown)
{
MessageBox.Show(
"Cannot enter NULL string as item!",
"Fatal error!", MessageBoxButtons.OK,
MessageBoxIcon.Error);
}
errshown = false;
}
else
{
errshown = false;
mllb.Items[index] = Text;
Hide();
}
base.OnLostFocus(e);
}
}
protected override void OnKeyDown(KeyEventArgs e)
{
if (e.KeyData == Keys.F2)
{
int index = SelectedIndex;
if (index == ListBox.NoMatches ||
index == 65535)
{
if (Items.Count > 0)
index = 0;
}
if (index != ListBox.NoMatches &&
index != 65535)
{
string s = Items[index].ToString();
Rectangle rect = GetItemRectangle(index);
tbox.Location = new Point(rect.X, rect.Y);
tbox.Size = new Size(rect.Width, rect.Height);
tbox.Text = s;
tbox.index = index;
tbox.SelectAll();
tbox.Show();
tbox.Focus();
}
}
base.OnKeyDown(e);
}
}
}
我遇到的困难是，即使我已将文本框设置为应有的状态，列表视图项似乎仍将内容限制为 TextWrap，最多为 7.5 行。
图片参考 http://imageshack.us/a/img819/9345/5nh4.png
在第 32 行foreach (string line in s.Split(new string[] { Environment.NewLine }, StringSplitOptions.None))，我尝试查找要在 OnMeasureItem 覆盖中返回的字符串中最长文本行的长度，但它拒绝超出假定的限制。任何帮助将不胜感激。