I want to align my text in combo box so that it will show in the center of combobox tell me how to do this also you can see there is a default border around a combo box when it is in focus how can i remove that border also Kindly solve my two problems Thanks
This isn't supported for ComboBox. The exact reasons are lost in the fog of time, ComboBox has been around since the early nineties, but surely has something to do with the awkwardness of getting the text in the textbox portion to line up with the text in the dropdown. Custom drawing with DrawItem cannot solve it either; that only affects the appearance of the dropdown items.
As a possible workaround, you could perhaps do something outlandish like padding the item strings with spaces so they look centered. You'll need TextRenderer.MeasureText() to figure out how many spaces to add for each item.
The "border" you are talking about is not a border, it is the focus rectangle. You can't get rid of that either. Windows refuses to let you create a UI that won't show the control with the focus. Users that prefer the keyboard over the mouse care about that. No workaround for that one.