/// <summary>
/// repostion SelectionStart, recalculate SelectedLength
/// </summary>
protected override void OnKeyPress(KeyPressEventArgs e)
{
base.OnKeyPress(e);
if (ReadOnly)
{
return;
}
if (e.KeyChar == (char)13 || e.KeyChar == (char)3 || e.KeyChar == (char)22 || e.KeyChar == (char)24)
{
return;
}
if (m_decimalLength == 0 && e.KeyChar == m_decimalSeparator)
{
e.Handled = true;
return;
}
if (!m_allowNegative && e.KeyChar == m_negativeSign && base.Text.IndexOf(m_negativeSign) < 0)
{
e.Handled = true;
return;
}
if (!char.IsDigit(e.KeyChar) && e.KeyChar != m_negativeSign && e.KeyChar != m_decimalSeparator)
{
e.Handled = true;
return;
}
if (base.Text.Length >= m_MaxValueLength && e.KeyChar != m_negativeSign)
{
e.Handled = true;
return;
}
if (e.KeyChar == m_decimalSeparator || e.KeyChar == m_negativeSign) // will position after dot(.) or first
{
SelectionLength = 0;
}
var isNegative = base.Text[0] == m_negativeSign ? true : false;
if (isNegative && SelectionStart == 0)
{
SelectionStart = 1;
}
if (e.KeyChar == m_negativeSign)
{
var selStart = SelectionStart;
if (!isNegative)
{
base.Text = m_negativeSign + base.Text;
SelectionStart = selStart + 1;
}
else
{
base.Text = base.Text.Substring(1, base.Text.Length - 1);
if (selStart >= 1)
{
SelectionStart = selStart - 1;
}
else
{
SelectionStart = 0;
}
}
e.Handled = true; // minus(-) has been handled
return;
}
var dotPos = base.Text.IndexOf(m_decimalSeparator) + 1;
if (e.KeyChar == m_decimalSeparator)
{
if (dotPos > 0)
{
SelectionStart = dotPos;
}
e.Handled = true; // dot has been handled
return;
}
if (base.Text == "0")
{
BaseText.SelectAll(); //清除默认0
//this.SelectionStart = 0;
//this.SelectionStart = 1; // replace thre first char, ie. 0
}
else if (base.Text == m_negativeSign + "0")
{
SelectionStart = 1;
SelectionLength = 1; // replace thre first char, ie. 0
}
else if (m_decimalLength > 0)
{
if (base.Text[0] == '0' && dotPos == 2 && SelectionStart <= 1)
{
SelectionStart = 0;
SelectionLength = 1; // replace thre first char, ie. 0
}
else if (base.Text.Substring(0, 2) == m_negativeSign + "0" && dotPos == 3 && SelectionStart <= 2)
{
SelectionStart = 1;
SelectionLength = 1; // replace thre first char, ie. 0
}
else if (SelectionStart == dotPos + m_decimalLength)
{
SelectionStart -= 1;
SelectionLength = 1; // last position after text
}
else if (SelectionStart >= dotPos)
{
SelectionLength = 1;
}
else if (SelectionLength == dotPos + m_decimalLength)
{
ClearSelection();
SelectionStart = 0;
SelectionLength = 1;
}
}
}