I want to increase an int variable i whenever I click on a button. But what I get is only int value of 1 and it doesn't increase anymore.
Here is my code:
private int i;
protected void btnStart_Click(object sender, EventArgs e)
{
i++;
lblStart.Text = i.ToString();
}
By each request (Clicking on the button), a new instance will be created.
So your non-static variable will be reset to 0.
You can define i as static:
private static int i;
protected void btnStart_Click(object sender, EventArgs e)
{
i++;
lblStart.Text = i.ToString();
}
But please note that the i variable is shared between all the users.
To improve this issue, you can use Session.
Session is an ability to store data of each user in a session.
So you can use following property to change the i variable in each session:
private int i
{
get
{
if (Session["i"] == null)
return 0;
return (int)Session["i"];
// Instead of 3 lines in the above, you can use this one too as a short form.
// return (int?) Session["i"] ?? 0;
}
set
{
Session["i"] = value;
}
}
protected void btnStart_Click(object sender, EventArgs e)
{
i++;
lblStart.Text = i.ToString();
}
As you know other answer is correct i want add another answer
You must in webform save your variables in ViewState
Just define your variables like this
public int i
{
get { Convert.ToInt32( ViewState["i"] ); }
set { ViewState["i"] = value ; }
}
Convert lblStart.Text value to int every time and assign it to i. Then increase i.
private int i;
protected void btnStart_Click(object sender, EventArgs e)
{
i = Int32.Parse(lblStart.Text);
i++;
lblStart.Text = i.ToString();
}
I have similar questions as yours and I believe the issue is because the event click did not store the value that has been increased before, therefore it could not be incremented the next time you clicked, so here's my code:
protected void btn_add_Click(object sender, EventArgs e)
{
string initial;
int increment;
int quantity;
initial = TextBoxQty.Text;
increment = Convert.ToInt16(initial);
increment++;
TextBoxQty.Text = increment.ToString();
quantity = increment;
}
You can use a hidden field, initialize them to 0.
private int i;
protected void btnStart_Click(object sender, EventArgs e)
{
i = int.Parse(myHiddenField.Value);
i++;
myHiddenField.Value = i;
lblStart.Text = i.ToString();
}
protected static int a = 0;
protected void btnStart_Click(object sender, EventArgs e)
{
a = a+1;
lblStart.Text = i.ToString();
}
It Works for me but on page_load() it initiates the value from 1 again !
this is actually my first time doing this
int i = 0;
while (i>=0)
{
Console.WriteLine(i);
Console.ReadLine();
i++;
}
Related
I want to increase values on timer tick event but it is not increasing don't know what I am forgetting it is showing only 1.
<asp:Timer ID="Timer1" runat="server" OnTick="Timer1_Tick" Interval="1000"></asp:Timer>
private int i = 0;
protected void Timer1_Tick(object sender, EventArgs e)
{
i++;
Label3.Text = i.ToString();
}
You can use ViewState to store and then read the value of i again.
int i = 0;
protected void Timer1_Tick(object sender, EventArgs e)
{
//check if the viewstate with the value exists
if (ViewState["timerValue"] != null)
{
//cast the viewstate back to an int
i = (int)ViewState["timerValue"];
}
i++;
Label3.Text = i.ToString();
//store the value in the viewstate
ViewState["timerValue"] = i;
}
Check whether the form is posted back and then assign values. Check IsPostBack
private int i;
protected void Timer1_Tick(object sender, EventArgs e)
{
if (!IsPostBack)
{
i = 0;
}
else
{
i = Int32.Parse(Label3.Text);
i++;
}
Label3.Text = i.ToString();
}
Generally speaking it is not a good practice to store values inside of views (such as asp.net page). It could be overwritten each time the request is sent.
You could store your data elsewhere:
public static class StaticDataStorage
{
public static int Counter = 0;
}
And use it:
protected void Timer1_Tick(object sender, EventArgs e)
{
StaticDataStorage.Counter++;
Label3.Text = StaticDataStorage.Counter.ToString();
}
I want to increase values on timer tick event but it is not increasing don't know what I am forgetting it is showing only 1.
<asp:Timer ID="Timer1" runat="server" OnTick="Timer1_Tick" Interval="1000"></asp:Timer>
private int i = 0;
protected void Timer1_Tick(object sender, EventArgs e)
{
i++;
Label3.Text = i.ToString();
}
You can use ViewState to store and then read the value of i again.
int i = 0;
protected void Timer1_Tick(object sender, EventArgs e)
{
//check if the viewstate with the value exists
if (ViewState["timerValue"] != null)
{
//cast the viewstate back to an int
i = (int)ViewState["timerValue"];
}
i++;
Label3.Text = i.ToString();
//store the value in the viewstate
ViewState["timerValue"] = i;
}
Check whether the form is posted back and then assign values. Check IsPostBack
private int i;
protected void Timer1_Tick(object sender, EventArgs e)
{
if (!IsPostBack)
{
i = 0;
}
else
{
i = Int32.Parse(Label3.Text);
i++;
}
Label3.Text = i.ToString();
}
Generally speaking it is not a good practice to store values inside of views (such as asp.net page). It could be overwritten each time the request is sent.
You could store your data elsewhere:
public static class StaticDataStorage
{
public static int Counter = 0;
}
And use it:
protected void Timer1_Tick(object sender, EventArgs e)
{
StaticDataStorage.Counter++;
Label3.Text = StaticDataStorage.Counter.ToString();
}
In ASP.NET I could use sessions for it but for windows form how can I get current value to which I can add + 1?
After btnPrintToken click it would override, re-run the code, I want it to keep the last entered value(LastTokenNumberIssued) and for it to add + 1 and so on so it will update the queue.
private void btnPrintToken_Click(object sender, EventArgs e)
{
Queue<int> queueTokens = new Queue<int>();
lblStatus.Text = "There are " + queueTokens.Count.ToString() +
" customers before you in the queue";
int LastTokenNumberIssued = // Not sure how to retrieve current value what it was after nextTokenNumberTobeIssued.
int nextTokenNumberTobeIssued = LastTokenNumberIssued + 1;
LastTokenNumberIssued = nextTokenNumberTobeIssued;
queueTokens.Enqueue(nextTokenNumberTobeIssued);
AddTokensToListBox(queueTokens);
}
private void AddTokensToListBox(Queue<int> queueTokens)
{
listTokens.Items.Clear();
foreach (int token in queueTokens)
{
listTokens.Items.Add(token.ToString());
}
}
Create your LastTokenNumberIssued outside the method:
public YourWindow
{
int LastTokenNumberIssued;
private void btnPrintToken_Click(object sender, EventArgs e)
{
int nextTokenNumberIssued;
LastTokenNumberIssued = LastTokenNumberIssued++;
nextTokenNumberTobeIssued = LastTokenNumberIssued;
}
}
If you create LastTokenNumberIssued inside the method, it will get overridden everytime you click the button because its value is lost when the method returns.
Check this for more info on method scope.
One way to do this, is by defining these variables nextTokenNumberTobeIssued, LastTokenNumberIssued before the btnPrintToken_Click method, something like this:
int LastTokenNumberIssued = 0; //give it a default value here.
int nextTokenNumberTobeIssued = 0; //give it a default value here.
private void btnPrintToken_Click(object sender, EventArgs e)
{
....
nextTokenNumberTobeIssued = LastTokenNumberIssued + 1;
LastTokenNumberIssued = nextTokenNumberTobeIssued;
...
}
This way each time the user click the button PrintToken, you will have the LastTokenNumberIssued holds the previous click.
int LastTokenNumberIssued = 0; //here will be the start value
private void btnPrintToken_Click(object sender, EventArgs e)
{
Queue<int> queueTokens = new Queue<int>();
lblStatus.Text = "There are " + queueTokens.Count.ToString() +
" customers before you in the queue";
int nextTokenNumberTobeIssued = LastTokenNumberIssued + 1;
LastTokenNumberIssued = nextTokenNumberTobeIssued;
queueTokens.Enqueue(nextTokenNumberTobeIssued);
AddTokensToListBox(queueTokens);
}
private void AddTokensToListBox(Queue<int> queueTokens)
{
listTokens.Items.Clear();
foreach (int token in queueTokens)
{
listTokens.Items.Add(token.ToString());
}
}
I have a counter that onclick should increment 1 and it does that on click, but if I click the button again, it won't increment again. Instead it will be stuck at 1. How can I make it go up if the button is clicked more than once?
protected void submitAnswerButton_Click(object sender, EventArgs e)
{
int counter = 0;
if (mathAnswerTextBox.Text == answer.ToString())
{
answerStatus.Text = "Correct!";
}
else if (mathAnswerTextBox.Text != answer.ToString())
{
answerStatus.Text = "Incorrect";
counter++;
if (counter == 1)
{
incorrectStrikes.Text = counter.ToString();
}
else if (counter == 2)
{
incorrectStrikes.Text = counter.ToString();
}
else if (counter == 3)
{
incorrectStrikes.Text = counter.ToString();
}
}
You would need to make counter outside of the method, such as a field in the class, not a local variable:
private int counter = 0;
protected void submitAnswerButton_Click(object sender, EventArgs e)
{
if (mathAnswerTextBox.Text == answer.ToString())
{
answerStatus.Text = "Correct!";
...
Since this is a web application you'd probably want to store the counter in the session, something like:
Inside Page_Load:
if(!IsPostback)
{
Session["AttemptCount"] = 0
}
And then inside
protected void submitAnswerButton_Click(object sender, EventArgs e)
{
int counter = (int)Session["AttemptCount"];
if (mathAnswerTextBox.Text == answer.ToString())
{
answerStatus.Text = "Correct!";
...
//Make sure you include this on all paths through this method that
//affect counter
Session["AttemptCount"] = counter;
As it stands you counter is a local variable (as in below code) and so every time you click button it will get initialized to 0 and hence you get 1 every time cause it's getting incremented once.
protected void submitAnswerButton_Click(object sender, EventArgs e)
{
int counter = 0;
You'll need to store the value in a more global context, eg ViewState or Session or maybe even a HiddenField for storage of the value.
Conclusio: Web is stateless so you'd need a state-manager.
protected void submitAnswerButton_Click(object sender, EventArgs e)
{
var counter = this.ViewState["foo"] as int; // read it from the ViewState from the previous request, or set it to default(int) = 0 with as
// ... do your routine
this.ViewState["foo] = counter; // write it back to store it for the next request
}
Anyway - this is just valid in a web-context where you are stateless.
If you were in a webform/wpf-context you would rather go for a simple static, or instance-variable, or ... (whatever suits your current need, architecture, ...)
I am very new to programming and I am trying to do that every time you click a button, it adds one to the value of an int and shows it in a textbox. My code is:
private void button1_Click(object sender, EventArgs e)
{
int a = 100;
a++;
txtBox1.Text = a.ToString();
}
So when I click the button it shows in the text box 101, but when I click it again, I want the textbox to show 102 and 103 etc etc. Any ideas? I assume it's very easy and using some variation of a loop but I have tried a few things and nothing seems to work. Any tips would be greatly appreciated! Thanks.
You have to store your value outside of Method Body.
private int a = 100;
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
What you did in your program is anytime you clicked the button, new Integer a was declared with value of 100, then you are increasing it by 1 and that's why you always seen '101'.
In your code you delcare a and assign a value to it over and over again every time you click on the button.
You should declare the variable outside of button1_Click method:
class Window1
{
int a = 100;
....
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
}
You need to declare a as a member of the class containing your method:
private int _a = 100;
private void button1_Click(object sender, EventArgs e)
{
_a++;
txtBox1.Text = _a.ToString();
}
If you don't do that, you will have a new instance every time the button is clicked, so you will always see 101 in your text box.
It is possible not to create global fields and store count of clicks inside the textbox.
This is especially convenient if you have several buttons.
private void button1_Click(object sender, EventArgs e)
{
if (txtBox1.Tag is int)
{
int a = (int)txtBox1.Tag;
a++;
txtBox1.Tag = a;
txtBox1.Text = a.ToString();
}
else
{
txtBox1.Tag = 100;
txtBox1.Text = 100;
}
}
int a = 100;
txtBox1.Text = a.ToString();
......
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
Placing int a = 100; inside the button1_Click(object sender, EventArgs e) will set a to 100 when each time function executing. If you need to have a counter place it outside from the function(Then it will initialize only once.) and increment it when executing the function.
Solution
int a = 100;
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
static int a = 100;
private void button1_Click(object sender, EventArgs e)
{
a++;
txtBox1.Text = a.ToString();
}
if you want to optimization your code than firstly set the textbox property text = 100 and write only one line code in button click event
private void button1_Click(object sender, EventArgs e)
{
txtBox1.Text = (Convert.ToInt32(txtBox1.Text) + 1).ToString();
}
as you know C# complie the code line by line and you have only one line code than it's give faster perfomance.