CODEWITHSUNDEEP
c#asp.netcheckbox
onTheInternet
onTheInternet

Reputation: 7263

how to run method after check box is checked

I am building a form on an aspx page. I want to run a method that will add more fields and labels if the user ticks a checkbox labeled 'recurring donation?'

My Form 

        <telerik:LayoutRow CssClass="formContainer">
            <Columns>
                <telerik:LayoutColumn Span="12" SpanSm="12" SpanMd="12">
                    <asp:Label id="firstName" runat="server"></asp:Label>
                    <br />
                    <asp:TextBox runat="server" ID="UserFirstName"></asp:TextBox>
                </telerik:LayoutColumn>
                <telerik:LayoutColumn Span="12" SpanSm="12" SpanMd="12">
                    <asp:Label id="lastName" runat="server"></asp:Label>
                    <br />
                    <asp:TextBox runat="server" ID="UserLastName"></asp:TextBox>
                </telerik:LayoutColumn>
                <telerik:LayoutColumn Span="3" SpanSm="12" SpanMd="12">
                    <asp:Label id="address1" runat="server"></asp:Label>
                    <br />
                    <asp:TextBox runat="server" ID="userAddress1"></asp:TextBox>
                </telerik:LayoutColumn>
                <telerik:LayoutColumn Span="9" SpanSm="12" SpanMd="12">
                    <asp:Label id="address2" runat="server"></asp:Label>
                    <br />
                    <asp:TextBox runat="server" ID="userAddress2"></asp:TextBox>
                </telerik:LayoutColumn>
                <telerik:LayoutColumn Span="3" SpanMd="12" SpanSm="12">
                    <asp:Label ID="city" runat="server"></asp:Label>
                    <br />
                    <asp:TextBox runat="server" ID="userCity"></asp:TextBox>
                </telerik:LayoutColumn>
                <telerik:LayoutColumn Span="9" SpanMd="12" SpanSm="12">
                    <asp:Label ID="zip" runat="server"></asp:Label> 
                    <br />
                    <asp:TextBox ID="userZip" runat="server"></asp:TextBox>
                </telerik:LayoutColumn>
                <telerik:LayoutColumn>
                    <asp:Label ID="returningDonor" runat="server"></asp:Label>
                    <br />
                    <asp:CheckBox ID="userReturningDonor" runat="server" />
                </telerik:LayoutColumn>
            </Columns>
        </telerik:LayoutRow>

And my code behind

public partial class donationForm : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        firstName.Text = "First Name";
        lastName.Text = "Last Name";
        address1.Text = "Address 1";
        address2.Text = "Address 2";
        city.Text = "City";
        zip.Text = "Zip Code";
        returningDonor.Text = "Recurring Donation?";

        userReturningDonor.Checked = showRecuring();
    }
    static void showRecuring()
    {
        /*RUN CODE*/
    }
}

The error im getting is

Cannot implicity convert type 'void' to 'bool'

Upvotes: 2

Views: 1465

Answers (4)

Tony L.
Tony L.

Reputation: 19486

There's a few things to try here depending on what you want to accomplish:

Cause a post back when checkbox is clicked

If you actually want it to post back and run code right when it's checked, I would do this:

Update your checkbox like so:

<asp:CheckBox ID="userReturningDonor" runat="server" OnCheckedChanged="userReturningDonor_CheckedChanged" AutoPostBack="true" />

Add this to the code behind:

protected void userReturningDonor_CheckedChanged(object sender, EventArgs e)
{
    if (userReturningDonor.Checked) {
        MsgBox("Checked");
    } else {
        MsgBox("Not checked");
    }
}

Just get rid of the error

If you just want to get rid of the error but your code still runs as expected, then you could do this:

Change static void showRecuring() to static bool showRecuring()

donationForm is expecting showRecuring to return a boolean in this line:

userReturningDonor.Checked = showRecuring();

However, showRecuring is a void.

This will get rid of your error, but if you want showRecuring to run code based on whether or not userReturningDonor.Checked then you could do something like this:

Just run function in the Page_Load event

Replace userReturningDonor.Checked = showRecuring(); with showRecuring(userReturningDonor.Checked);

and define showRecuring like so:

static void showRecuring(bool returningDonorChecked){
    if(returningDonorChecked) {
        //yes
    } else {
        //no
    }
}

Upvotes: 2

bowlturner
bowlturner

Reputation: 2016

Your static method showRecuring is not returning any values (like a bool) but you are using it in the call as it should.

userReturningDonor.Checked = showRecuring();

static void showRecuring()

should be 

static bool showRecuring()

Upvotes: 1

psoshmo
psoshmo

Reputation: 1560

Checked

is a bool that gets or set the status of the checkbox (checked or unchecked). if you want to do something when the box is checked, you want to handle the checkbox's CheckedChanged event. so you want something like

 userReturningDonor.CheckedChanged += showRecuring(usinderReturningDonor, new EventArgs());

and

 static void showRecuring(object sender, EventArgs e)
{
    /*RUN CODE*/
}

EDIT: Just to be clear, the Checked property of the checkbox is NOT how you handle when it is checked. It is how you tell if it is currently checked or how you set it to be checked or unchecked.

EDIT 2: As other have pointed out, you are getting an error because the Checked property expects a true or false, where your method returns void. However, Changing your method to return a bool wont help you in your desire to run some code when a checkbox becomes checked

Upvotes: 1

Kyle Trauberman
Kyle Trauberman

Reputation: 25694

You are setting the return value of showRecurring() to the checked property of userReturningDonor, which expects a bool.

Change the return type of showRecurring() to a bool.

static bool showRecuring()
{
    /*RUN CODE*/
}

Upvotes: 1

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