/// <summary>
/// Gets the selection start and length.
/// </summary>
/// <param name="start">Start of selection.</param>
/// <param name="length">Length of selection.</param>
public void GetSel(out int start, out int length)
{
int liEnd = 0;
EnhTextBoxAPIFunctions.SendMessageLongRef(Handle, EnhTextBoxAPIFunctions.Messages.EM_GETSEL, out start, out liEnd);
length = liEnd - start;
}
/// <summary>
/// Locks the window so that no redrawing occurs.
/// </summary>
public void LockWindow()
{
if (miLockCount == 0)
{
mbSuspendPainting = true;
EnhTextBoxAPIFunctions.SendMessageLong(Handle, EnhTextBoxAPIFunctions.Messages.WM_SETREDRAW, 0, 0);
}
;
miLockCount++;
}
/// <summary>
/// Sets the scoll position of the text box.
/// </summary>
/// <remarks>This code compensates for the EM_GETSCROLLPOS message limitations.</remarks>
/// <param name="value">The new scroll position.</param>
protected void SetScrollPos(Point value)
{
// Save the original value
EnhTextBoxAPIFunctions.POINTAPI lpOriginal = (EnhTextBoxAPIFunctions.POINTAPI)value;
if (lpOriginal.Y < 0)
{
lpOriginal.Y = 0;
}
if (lpOriginal.X < 0)
{
lpOriginal.X = 0;
}
// Default factored value to original value with Y Factor compensation
EnhTextBoxAPIFunctions.POINTAPI lpFactored = (EnhTextBoxAPIFunctions.POINTAPI)value;
lpFactored.Y = (int)((double)lpOriginal.Y * mdScrollPosYfactor);
// Current result
EnhTextBoxAPIFunctions.POINTAPI lpResult = (EnhTextBoxAPIFunctions.POINTAPI)value;
EnhTextBoxAPIFunctions.SendMessagePoint(this.Handle, EnhTextBoxAPIFunctions.Messages.EM_SETSCROLLPOS, 0, ref lpFactored);
EnhTextBoxAPIFunctions.SendMessagePoint(this.Handle, EnhTextBoxAPIFunctions.Messages.EM_GETSCROLLPOS, 0, ref lpResult);
int liLoopCount = 0;
int liMaxLoop = 100;
while (lpResult.Y != lpOriginal.Y)
{
// Adjust the input.
if (lpResult.Y > lpOriginal.Y)
{
lpFactored.Y -= (lpResult.Y - lpOriginal.Y) / 2 - 1;
}
else
if (lpResult.Y < lpOriginal.Y)
{
lpFactored.Y += (lpOriginal.Y - lpResult.Y) / 2 + 1;
}
// test the new input.
EnhTextBoxAPIFunctions.SendMessagePoint(this.Handle, EnhTextBoxAPIFunctions.Messages.EM_SETSCROLLPOS, 0, ref lpFactored);
EnhTextBoxAPIFunctions.SendMessagePoint(this.Handle, EnhTextBoxAPIFunctions.Messages.EM_GETSCROLLPOS, 0, ref lpResult);
// save new factor, test for exit.
liLoopCount++;
if (liLoopCount >= liMaxLoop || lpResult.Y == lpOriginal.Y)
{
mdScrollPosYfactor = (double)lpFactored.Y / (double)lpOriginal.Y;
break;
}
}
}
/// <summary>
/// Unlocks and invalidates the window to resume redrawing.
/// </summary>
public void UnlockWindow()
{
miLockCount--;
if (miLockCount == 0)
{
mbSuspendPainting = false;
EnhTextBoxAPIFunctions.SendMessageLong(Handle, EnhTextBoxAPIFunctions.Messages.WM_SETREDRAW, 1, 0);
Invalidate();
}
if (miLockCount < 0)
{
miLockCount = 0;
}
}
/// <summary>
/// Returns true if the selection is in a forward direction (cursor is after selection)
/// or false if the selection is in a backward direction (cursor is before selection).
/// </summary>
/// <returns>True if selection is forward.</returns>
protected bool IsSelectionForward()
{
EnhTextBoxAPIFunctions.POINTAPI lpCaretPos;
EnhTextBoxAPIFunctions.GetCaretPos(out lpCaretPos);
lpCaretPos.X++;
lpCaretPos.Y++;
int liCaretChar = GetCharIndexFromPosition(new Point(lpCaretPos.X, lpCaretPos.Y));
int liStart, liLength;
GetSel(out liStart, out liLength);
if (liLength > 0 && liCaretChar <= liStart)
{
return(false);
}
else
{
return(true);
}
}
/// <summary>
/// Sets the selection start and length.
/// </summary>
/// <param name="start">The start of the selection.</param>
/// <param name="length">The length of the selection.</param>
public void SetSel(int start, int length)
{
EnhTextBoxAPIFunctions.SendMessageLong(Handle, EnhTextBoxAPIFunctions.Messages.EM_SETSEL, start, start + length);
}
/// <summary>
/// Gets the scroll position of the text box.
/// </summary>
/// <returns>The point denoting the scroll position.</returns>
protected Point GetScrollPos()
{
EnhTextBoxAPIFunctions.POINTAPI lpScrollPoint = new EnhTextBoxAPIFunctions.POINTAPI();
EnhTextBoxAPIFunctions.SendMessagePoint(this.Handle, EnhTextBoxAPIFunctions.Messages.EM_GETSCROLLPOS, 0, ref lpScrollPoint);
return(new Point(lpScrollPoint.X, lpScrollPoint.Y));
}
