Creating a custom Multi-Line Listbox

Creating a custom Multi-Line Listbox

In the creation of some apps, a list-box with multiple lined content is
preferred. Since listboxes have no such function, the creation of a custom
control is needed. For this case, I'm working on a compiler app that the
user can load an import and export C# prefab into the program to
manipulate data. To see this compiler in action, you can check out my
previous post here. For this instance, I want a debug log of any errors to
be outputted into the listbox. Since some errors contain multiple lines,
some of which are rather long, I read up and generated a Listbox of
Textbox items.
The most current copy of this can be found on pastebin.
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);
}
}
}
The difficulty I'm having, is that, even though I've set the textbox as it
should be, the list view item still seems to be limiting content to
TextWrap, and a maximum of 7.5 lines.

On line 32 foreach (string line in s.Split(new string[] {
Environment.NewLine }, StringSplitOptions.None)) I try to find the length
of the longest line of text in the string to return in the OnMeasureItem
override, but it refuses to go in excess of the assumed limit. Any help
would be greatly appreciated.