I running into an infinite loop problem.
I have two numeric up/down controls (Height and Width input parameters). When the user changes the value of one of the controls, I need to scale the other to keep a height to width ratio constant.
Is there a way to set the value of a control without invoking a ValueChanged Event. I only want the ValueChanged event to execute when the user changes the value.
private void FloorLength_ValueChanged(object sender, EventArgs e)
{
if (this.mCurrentDocument.System.SuperTrakSystem.FloorBitmap != null)
{
FloorWidth.Value = FloorLength.Value *
((decimal)this.mCurrentDocument.System.SuperTrakSystem.FloorBitmap.Height /
(decimal)this.mCurrentDocument.System.SuperTrakSystem.FloorBitmap.Width);
}
}
private void FloorWidth_ValueChanged(object sender, EventArgs e)
{
if (this.mCurrentDocument.System.SuperTrakSystem.FloorBitmap != null)
{
FloorLength.Value = FloorWidth.Value *
((decimal)this.mCurrentDocument.System.SuperTrakSystem.FloorBitmap.Width /
(decimal)this.mCurrentDocument.System.SuperTrakSystem.FloorBitmap.Height);
}
}
Thanks for your answers.
I came up with an alternate solution that works. User changing the value from the UI triggers the event, while programmatic Value parameter changes do not trigger the event.
using System;
using System.Windows.Forms;
namespace myNameSpace.Forms.UserControls
{
public class NumericUpDownSafe : NumericUpDown
{
EventHandler eventHandler = null;
public event EventHandler ValueChanged
{
add
{
eventHandler += value;
base.ValueChanged += value;
}
remove
{
eventHandler -= value;
base.ValueChanged -= value;
}
}
public decimal Value
{
get
{
return base.Value;
}
set
{
base.ValueChanged -= eventHandler;
base.Value = value;
base.ValueChanged += eventHandler;
}
}
}
}
I'm not that familiar with the NumericUpDown control, but there may not be a way to set the value without triggering the ValueChanged event. Instead, before you set the value, you could set a flag indicating that the event should be ignored, and clear the flag after setting the value. In your event handler, do nothing if the flag is set.
private bool ignoreEvent = false;
private void setValue(int value)
{
ignoreEvent = true;
FloorLength.Value = value;
ignoreEvent = false;
}
private void FloorLength_ValueChanged(object sender, EventArgs e)
{
if(ignoreEvent) { return; }
// your code here
}
In theory, these values should stabilize... Meaning if the user changes 1, the system changes the other and then the first one remains the same. Therefore, I would just add a check into both of the event handlers (pseudocode):
newValue = equation;
if(controlValue != newValue)
{
controlValue = newValue; //raises the event only when necessary.
}
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With