Visualtreehelper of WPF ComboBox

Textchanged is required when you use the ComboBox control of WPF, but this property belongs to the Textbox Control. You don't have to worry about it. There is a textbox in ComboBox, so the key issue is how to find the Textbox Control in ComboBox.

Default ComboBox control composition:

The first layer (1 Control ):

System. Windows. Controls. Grid

Layer 2 (2 controls ):

System. Windows. Controls. primitives. Popup;

Microsoft. Windows. Themes. listboxchrome;

System. Windows. Controls. textbox;

System. Windows. Controls. primitives. togglebutton content: ischecked: false

Controls are arranged in order, so the Textbox Control is obtained as follows:

 
(Textbox) visualtreehelper. getchild (visualtreehelper. getchild (this. cbserver, 0), 2). textchanged + = new textchangedeventhandler (setdatabaseisenabled );
 

Note:CodeTo be placed in the window_loaded () event, it cannot be placed in the page constructor.

You can add the textchanged attribute to the ComboBox control.

PS: Find the code of the control in ComboBox:

 
Private void button#click (Object sender, routedeventargs e) {for (INT I = 0; I <visualtreehelper. getchildrencount (this. cbserver); I ++) {dependencyobject O1 = visualtreehelper. getchild (this. cbserver, I); For (Int J = 0; j <visualtreehelper. getchildrencount (O1); j ++) {dependencyobject O2 = visualtreehelper. getchild (O1, j );}}}