Numeric Control Problem

[pendragon]

I am writing a user control for number input, It also has a new property for the number of decimal places allowed and will not let you enter more than is specified.

 

Here is what I have so far.

 

using System;
using System.Windows.Forms;

namespace NumberDecimals
{
public class Number : TextBox
{
	private int noOfDecimals;

	public int NoOfDecimals
	{
		get 
		{
			return this.noOfDecimals;
		}
		set 
		{
			this.noOfDecimals = value;
		}
	}
	public Number()
	{
	}
	protected override void OnKeyPress(KeyPressEventArgs e)
	{
		base.OnKeyPress(e);

		if(this.noOfDecimals == 0) 
		{
			if(Char.IsNumber(e.KeyChar) || e.KeyChar == (char)8)
			{
				e.Handled = false; 
			}
			else 
			{
				e.Handled = true;
			}
		}
		else
		{
			bool bFoundDecimal = false;
			string sNumber, sSelected;
			int iCount, iLength, iNoAfterDecimal, iDecimalPosition;

			sSelected = this.SelectedText;
			sNumber = this.Text;
			iLength = this.TextLength;
			iDecimalPosition = 0;

			if (e.KeyChar == (char)46) 
			{
				if (sSelected != sNumber)
				{
					for (iCount = 0; iCount < iLength; iCount++) 
					{
						if (sNumber.Substring(iCount,1) == ".") 
						{
							bFoundDecimal = true;
							iCount = iLength;
						}
					}

					if(bFoundDecimal == true) 
					{
						e.Handled = true;
					}
					else 
					{
						e.Handled = false;
					}
				}
				else
				{
					e.Handled = false;
				}						 
			}
			else if (Char.IsNumber(e.KeyChar) || e.KeyChar == (char)8)
			{
				iDecimalPosition = iLength;
				for (iCount = 0; iCount < iLength; iCount++) 
				{
					if (sNumber.Substring(iCount,1) == ".") 
					{
						iDecimalPosition = iCount;
						iCount = iLength;
					}
				}

				if (iDecimalPosition == iLength || sSelected == sNumber) 
				{
					e.Handled = false;
				}
				else 
				{
					iNoAfterDecimal = iLength - iDecimalPosition;
					if (iNoAfterDecimal <= this.noOfDecimals || e.KeyChar == (char)8) 
					{
						e.Handled = false;
					}
					else 
					{
						e.Handled = true;
					}
				}
			}
			else 
			{
				e.Handled = true;
			}
		}
	}
}
}

 

This all works to a point.

 

If NoOfDecimals is set to 2 and 123.45 has been entered into the textbox, if the user whats to change it to 1123.45 then at the moment they have to remove the .45 before anything else can be entered.

 

Is there a way of finding the current postion of the curser in the textbox so I can check to see if it is to the left of the decimal.

 

Thank You.

[Bucky]

Yes, use the SelectionStart property.

[pendragon]

Thanks for that Bucky.

 

I thought SelectionStart was only set when you had highlighted some text, you learn something new every day.:D