« Home « Kết quả tìm kiếm

Using Controls Database to the Form Windows


Tóm tắt Xem thử

- Adding Controls to the Form.
- To make the form useful, you need to add controls and write some code of your own.
- In the next exercise, you will add controls to the form that allow a user to input member details.
- You will use a variety of different controls, each suited to a particular type of data entry..
- You will use TextBox controls for entering the first name and last name of the member..
- The form also records whether the member is the tower.
- only rings one bell at a time, a group of bell ringers under the direction of the tower captain can ring their bells in different sequences and generally play simple music.
- In this application, you will use a small selection of methods that you will hard-wire into the form.
- (You will see how to use databases in the next part of the book.) A good control for displaying this information and indicating whether a member can ring a method is the CheckedListBox..
- The user can click Clear to reset the controls on the form and cancel any data entered..
- Ensure that Form1 is displayed in the Designer View window.
- (If the Toolbox is not displayed, click Toolbox from the View menu, or click the Toolbox tab in the left-hand border of Visual Studio.) 2.
- In the Properties window, click the Location property, and then type 10,40 to set.
- the Location property of the label..
- From the Toolbox, drag a TextBox control onto MemberForm, to the right of the label.
- Do not worry about aligning the TextBox exactly because you will set the Location property for this and the following controls later..
- Add a second Label to the form.
- Place it to the right of the TextBox..
- Add another TextBox to MemberForm and position it to the right of the second Label..
- From the Toolbox, drag a third Label onto the form.
- From the Toolbox, drag a ComboBox control onto the form.
- Place it on MemberForm under the first TextBox and to the right of the third Label..
- From the Toolbox, drag a CheckBox control onto the form and place it under the second TextBox..
- From the Toolbox, drag a DateTimePicker control and place it under the ComboBox..
- In the Toolbox, expand the Containers category.
- From the Common Controls category in the Toolbox, drag the RadioButton control and place it inside the GroupBox control you just added..
- Add three more RadioButton controls, vertically aligned with each other, to the GroupBox.
- From the Toolbox, drag a CheckedListBox control and place it under the second Label and to the right of the GroupBox control..
- Add another Button control to the bottom of the form, just to the right of the first..
- You now need to set the properties of the controls you just added to the form.
- To change the value of a control's property, click the control on the form to select it, and then enter the correct value in the Properties window.
- You will start with the basic properties.
- The following table lists the properties and values you need to assign to each of the controls..
- DropDownList (This setting forces users to pick one of the items in the list.
- MiddleLeft (This property specifies the location of the checkbox relative to the text in the control.
- When you click the drop-down arrow for this property, an.
- Click the left square in the middle row.).
- You can click the drop-down arrow in this property to display a simple text editor that also allows you to enter multi-line text values).
- Location 16, 32 (Note that this location is relative to the radio button's container, the experience GroupBox.) Text Up to 1 year.
- If you want to learn more about the different properties available for each type of control, you can find a list of them in the MSDN Library for Visual Studio 2005 supplied with Visual Studio 2005..
- When the form runs, it would be useful to reset the value of each control to an initial default value.
- To do this, you will need to write some code (at last).
- In the following exercises, you will create a private method called Reset.
- Later, you will invoke the Reset method when the form first starts, and when the user clicks the Clear button..
- Rather than coding the method from scratch, you will use the Class Diagram editor to generate the method.
- Create the Reset method.
- In the Solution Explorer, right-click Form1.cs.
- Right-click the MemberForm class in the diagram, point to Add, and then click Method.
- In the Class Details pane that appears underneath the class diagram, verify that the Type of the Reset method is void, and that the Modifier is public.
- If they are wrong, you can click these fields in the Class Details pane and modify them..
- If the Class Details pane is not visible, click the Class Details tab below the Error List pane to display it..
- In the Class Details pane that appears underneath In the Class Diagram, right-click the Reset method and then click View Code..
- You are placed in the Code and Text Editor window displaying the MemberForm class.
- The Reset method has been added with a default implementation that throws a NotImplementedException:.
- In the Code And Text Editor window, replace the throw statement in the Reset method with the following lines of code:.
- firstName.Text .
- lastName.Text .
- You now need to configure the properties of the remaining controls on the form.
- You will do this programmatically..
- If you recall, the towerName ComboBox will contain a list of all the bell towers in the Middleshire district.
- A ComboBox has a property called Items that contains a list of the data to be displayed..
- In the Reset method, after the code you have already written, add the following.
- statements to clear this list (this is important because otherwise you would end up with many duplicate values in the list) and create four items in the ComboBox:.
- towerNames.Items.Clear();.
- towerNames.Items.Add("Great Shevington");.
- towerNames.Items.Add("Little Mudford");.
- towerNames.Items.Add("Upper Gumtree");.
- towerNames.Items.Add("Downley Hatch");.
- The next step is to initialize the memberSince DateTimePicker control to the current date..
- You can obtain the current date by using the static property Today of the DateTime class.
- Add the following statement to the Reset method:.
- The form contains four radio buttons that indicate the number of years of bell ringing experience the member has.
- By default, none of the buttons will be selected.
- You should rectify this by setting the Checked property of the novice radio button.
- However, as before, you will supply some hard-coded values for now.
- Complete the Reset method by adding the following code:.
- methods.Items.Clear();.
- methods.Items.Add("Canterbury Minimus");.
- methods.Items.Add("Reverse St Nicholas");.
- methods.Items.Add("Plain Bob Doubles");.
- methods.Items.Add("Grandsire Doubles");.
- methods.Items.Add("Cambridge Minor");.
- methods.Items.Add("Old Oxford Delight Minor");.
- methods.Items.Add("Kent Treble Bob Major");.
- Call the Reset method.
- You need to arrange for the Reset method to be called when the form is first displayed.
- A good place to do this is in the MemberForm constructor.
- In the Code And Text Editor window, scroll to the beginning of the MemberForm class in the file Form1.cs, and find the constructor (it is called MemberForm, just like the class).
- Insert a call to the Reset method after the statement that calls the InitializeComponent method:.
- It is a good practice to name the file containing a form after the form itself.
- In the Solution Explorer, right-click Form1.cs, click Rename, and then type.
- When the form runs, click the Tower ComboBox..
- You will see the list of bell towers, and you can select one of them..
- Click the drop-down arrow on the right side of the Member Since date/time picker..
- You will be presented with a calendar of dates.
- You can also click the month name to display the months as a drop-down list, and click the year to allow you to select a year using a numeric up-down control..
- Click each of the radio buttons in the Experience group..
- In the Methods list box, click some of the methods and select the corresponding check box.
- You will have to click once to select a method and a second time to select or clear the checkbox..
- Close the form and return to Visual Studio 2005.

Xem thử không khả dụng, vui lòng xem tại trang nguồn
hoặc xem Tóm tắt