SplitterContainer control with a fixed panel is resized due to the DPI setting, the
SplitterDistance value is not changed. This may result in the fixed panel appearing either too small or too large, depending on whether the DPI setting was increased or decreased.
For example, a Form with
AutoScaleMode set to
ScaleMode.DPI, and a
FixedPanel set to
SplitterDistance set to 140 appears as follows at it's native DPI (100%):
This is how it appears when run at a higher DPI (125%):
All the controls were resized, but
SplitterDistance was left unchanged at 140.
Note that this is only a problem when
SplitterContainer.FixedPanel is set to
Panel2. If it was set to
SplitterDistance would be adjusted to match the resizing.
The solution to adjust
SplitterDistance during the
Form.Shown event handler. The resizing does not work properly if performed in the constructor or the
Form.Load event handler.
Using the code
Include the following code snippet in your Form-derived class:
private SizeF scale = new SizeF(1.0f, 1.0f);
protected override void ScaleControl(SizeF factor, BoundsSpecified specified)
scale = new SizeF(scale.Width * factor.Width, scale.Height * factor.Height);
private void Fix(Control c)
foreach (Control child in c.Controls)
if (child is SplitContainer)
SplitContainer sp = (SplitContainer)child;
private void Fix(SplitContainer sp)
float sc = (sp.Orientation == Orientation.Vertical) ? scale.Width : scale.Height;
if (sp.FixedPanel == FixedPanel.Panel1)
sp.SplitterDistance = (int)Math.Round((float)sp.SplitterDistance * sc);
else if (sp.FixedPanel == FixedPanel.Panel2)
int cs = (sp.Orientation == Orientation.Vertical) ? sp.Panel2.ClientSize.Width :sp.Panel2.ClientSize.Height;
int newcs = (int)((float)cs * sc);
sp.SplitterDistance -= (newcs - cs);
Remember to call
Fix(this) from the Form's
Shown event handler. For Example:
private void Form1_Shown(object sender, EventArgs e)
Points of Interest
I am puzzled as to why the SplitterDistance values must be adjusted during the
event handler, and not during
Form.Load or the constructor. If anyone can explain this, please leave a comment.
- June 14, 2014 - First release.