Swicth windows in a WPF applications

[Hamza]

Hi , I'm trying to automate the testing of a WPF program by writing code. I can perform actions on the main window of the program, but I can't do it on a different window. I think the reason for this is that it doesn't recognize that window. However, I couldn't find out how to switch to a different window.Can you help me ?. Here's an example of the code I've written:
        [CodedStep(@"Type 'XXX' into ServerNameWatermarkTextbox")]
        public void ConfirmInstalledDate_CodedStep()
        {
            string formattedDate = DateTime.Now.ToString("yyyy-MM-dd");
            ActiveApplication.MainWindow.Find.ByName("serverNameWatermark").User.TypeText("XXX",2);
            ActiveApplication.MainWindow.Find.ByName("usernameWaterMark").User.TypeText("logadmin",2);         
            ActiveApplication.MainWindow.Find.ByName("usernameWaterMark").KeyPress(ArtOfTest.WebAii.Win32.KeyBoard.KeysFromString("Tab"),1,1,1);
            ActiveApplication.MainWindow.Find.ByName("pwdBox").User.TypeText("XXX",2);
            ActiveApplication.MainWindow.Find.ByName<Button>("btnSignIn").User.Click();
            System.Threading.Thread.Sleep(5000);
            ActiveApplication.MainWindow.Find.ByName("imgData").User.Click();
            ActiveApplication.MainWindow.Find.ByTextContent("Status").User.Click(MouseClickType.RightClick);
            ActiveApplication.MainWindow.Find.ByTextContent("Select columns").User.Click();
            ActiveApplication.GetWindow("Select columns");
            ActiveApplication.GetWindow("Select columns").Find.ByName("txtSearch").User.TypeText("Date",2); 
            System.Threading.Thread.Sleep(5000);
            ActiveApplication.GetWindow("Select columns").Find.ByName("txtSearch").User.KeyPress(System.Windows.Forms.Keys.Enter,1);
            ActiveApplication.MainWindow.Find.ByTextContent("^"+formattedDate).User.Click();
            System.Threading.Thread.Sleep(2000);
        }
    }

[Patrick]

I think that the window you are trying to access needs to be created. Or you need to create an instance of that window in order to access it.

Window2 MyWindow = new Window2();

Something along those lines. Maybe do this on application start and see if you are able to access the second window.

[Hamza]

Thank for your reply.
I might have misrepresented myself. To elaborate on the issue, if I need to delve into the details: When I attempt to access a specific window, let's say 'Select Columns,' within the Window of a WPF application, it's akin to a pop-up window that appears within the program. However, despite using the code snippet 'ActiveApplication.MainWindow.Find.ByName("XXX").User.TypeText("XXX",2);' to interact with this 'Select Columns' window, it seems to prioritize the Main Window, neglecting any actions intended for the 'Select Column' window