How to make the ComboBox drop down list resize itself to fit the largest item?
This is very elegant solution:
private void AdjustWidthComboBox_DropDown(object sender, System.EventArgs e)
{
ComboBox senderComboBox = (ComboBox)sender;
int width = senderComboBox.DropDownWidth;
Graphics g = senderComboBox.CreateGraphics();
Font font = senderComboBox.Font;
int vertScrollBarWidth =
(senderComboBox.Items.Count>senderComboBox.MaxDropDownItems)
?SystemInformation.VerticalScrollBarWidth:0;
int newWidth;
foreach (string s in senderComboBox.Items)
{
newWidth = (int) g.MeasureString(s, font).Width
+ vertScrollBarWidth;
if (width < newWidth )
{
width = newWidth;
}
}
senderComboBox.DropDownWidth = width;
}
Adjust combo box drop down list width to longest string width http://www.codeproject.com/KB/combobox/ComboBoxAutoWidth.aspx
Source: Calculating ComboBox DropDownWidth in C#
Here's what I did to solve this, works great...
public class ImprovedComboBox : ComboBox
{
public ImprovedComboBox()
{
}
public object DataSource
{
get { return base.DataSource; }
set { base.DataSource = value; DetermineDropDownWidth(); }
}
public string DisplayMember
{
get { return base.DisplayMember; }
set { base.DisplayMember = value; DetermineDropDownWidth(); }
}
public string ValueMember
{
get { return base.ValueMember; }
set { base.ValueMember = value; DetermineDropDownWidth(); }
}
private void DetermineDropDownWidth()
{
int widestStringInPixels = 0;
foreach (Object o in Items)
{
string toCheck;
PropertyInfo pinfo;
Type objectType = o.GetType();
if (this.DisplayMember.CompareTo("") == 0)
{
toCheck = o.ToString();
}
else
{
pinfo = objectType.GetProperty(this.DisplayMember);
toCheck = pinfo.GetValue(o, null).ToString();
}
if (TextRenderer.MeasureText(toCheck, this.Font).Width > widestStringInPixels)
widestStringInPixels = TextRenderer.MeasureText(toCheck, this.Font).Width;
}
this.DropDownWidth = widestStringInPixels + 15;
}
}