Please check my code

Question

C# visual studio 2015, Windows Form. I have a text box and three labels. I want to write in text box only number and decimal place two. But I can not write in the text box as 0.52 or 052. If I write with . or 0 the program does not continue. I need, I can start write in textbox with 0.## if first 0 is problem then message box will show but the program will continue. Please help me at this regard.  

 

private void txtAPenPension_TextChanged(object sender, EventArgs e)

{

if (Regex.IsMatch(txtAPenPension.Text, " ^ [0-9]"))

{

txtAPenPension.Text = "";

}

double tk1, tkS1, tkD1;

tk1 = double.Parse(txtAPenPension.Text);

tkS1 = tk1 * 0.01;

tkD1 = tk1 + tkS1;

if (txtAPenPension.Text != "")

{

lblAPenPorishodh.Text = string.Format("{0:F2}", tk1);

lblAPenServiceCharge.Text = string.Format("{0:F2}", tkS1);

lblAPenDabi.Text = string.Format("{0:F2}", tkD1);

return;

}

}

private void txtAPenPension_KeyPress(object sender, KeyPressEventArgs e)

{

string senderText = (sender as TextBox).Text;

string senderName = (sender as TextBox).Name;

string[] splitByDecimal = senderText.Split('.');

int cursorPosition = (sender as TextBox).SelectionStart;

if (!char.IsControl(e.KeyChar)

&& !char.IsDigit(e.KeyChar)

&& (e.KeyChar != '.'))

{

e.Handled = true;

}

if (e.KeyChar == '.'

&& senderText.IndexOf('.') > -1)

{

e.Handled = true;

}

if (!char.IsControl(e.KeyChar)

&& senderText.IndexOf('.') < cursorPosition

&& splitByDecimal.Length > 1

&& splitByDecimal[1].Length == 2)

{

e.Handled = true;

}

}