c# 文本超长截断

private void SetStringTruncat(Static.LabelEx lbl)
{
string oldStr = lbl.Text;
if (string.IsNullOrEmpty(oldStr))
return; Graphics g = lbl.CreateGraphics();
string strNewStr = string.Empty;
for (int i = ; i < oldStr.Length; i++)
{
strNewStr = oldStr.Substring(, oldStr.Length - i) + "…";
SizeF sizeF = g.MeasureString(strNewStr, lbl.Font, , StringFormat.GenericTypographic);
if (sizeF.Width <= lbl.MaximumSize.Width - )
{
break;
}
}
g.Dispose();
if (strNewStr == oldStr + "…")
strNewStr = oldStr;
lbl.Text = strNewStr;
}