Develop Reference

C# / asp.net global Variables?

I have two buttons with on click functions
The 1st one gets assigned a variable when Clicked.
How do I get my second button to get the variable from the 1st button when I click button 2?
It doesn't seem to work. As the second button doesn't recognise the Variable.
Thanks
EDIT:
Just to clarify My code is generating a pdf. button 1 selects the url of the template to use. and in button 2 (the one generating the pdf) I want it to get the variable set from button 1 so it knows what template to use.
EDIT 2:
My code does work but only when I'm not using the ajax update panel. it seems that the variable I'm trying to set doesn't get set with AJAX

Your Button have Id, you get this button with his Id
Nota : You can add runat="server" in order to visualize in server side
<asp:Button id="Button1"
Text="Click "
OnClick="Btn1_Click"
runat="server"/>
<asp:Button id="Button2"
Text="Click "
OnClick="Btn2_Click"
runat="server"/>
void Btn2_Click(Object sender, EventArgs e)
{
Button1.Text = "test after click on button 2";
Template = ...;//Set your value
}
void Btn1_Click(Object sender, EventArgs e)
{
Button2.Text = "test after click on button 1";
//Here you can get your value after post.
var result = Template;
}
It's not subject but in delegate you can also get objet button by passing on sender argument.
var button = sender as Button; //You get button who raise event
In order to manage Template Path property.
public string Template
{
get
{
if(ViewState["Template"] != null)
{
return (string)ViewState["Template"];
}
}
set{ViewState["Template"] = value;}
}

i guess you are looking at accessing value of a variable inside the click event of button2 for which the value is set in the button1 click event ?
private string myPrivateString = "";
void Page_Load()//Not sure of correct method signature
{
if(Page.IsPostBack)
{
myPrivateString = Session["myPrivateString"];
}
}
void Button1_Click(object sender, EventArgs e)
{
//There will a postback before this gets executed
myPrivateString = "Value Set From Button 1";
Session["myPrivateString"] = myPrivateString;
}
void Button2_Click(object sender, EventArgs e)
{
//There will a postback before this gets executed
//Accessing myPrivateString here without setting value from session
//will return empty string as after PostBack its a new page thats rendered.
myPrivateString = Session["myPrivateString"]; // Or do it in the Page_Load event
}
I guess now you can get the value of inside the button2 click event.
Also read about ASP.NET Page lifecycle and how client side events like button clicks are handled by the ASP.NET framework.

Recognizing sender button control in click event

I made a custom button that has a field named Data.
I add this button programatically during runtime to my winform and on adding I also define a click event for them. Well, Actually I only have one method and I subscribe the newly added buttons to this method.
But in the click event I want to access this Data field and show it as a message box, but it seems that my casting is not right:
CustomButton_Click(object sender, EventArgs e)
{
Button button;
if (sender is Button)
{
button = sender as Button;
}
//How to access "Data" field in the sender button?
//button.Data is not compiling!
}
UPDATE:
I am sorry, I ment with "is not compiling" that .Data does not show up in intelisense...

You need to cast to the type of your custom class that has the Data field.
Something like:
YourCustomButton button = sender as YourCustomButton;

Assuming your custom button type is CustomButton, you should do this instead:
CustomButton_Click(object sender, EventArgs e){
CustomButton button = sender as CustomButton;
if (button != null){
// Use your button here
}
}

If you dont want to set a variable the simple way to do is:
((CustomButton)sender).Click
or whatever you want.

I found a funny check assignment in a win forms project on Github:
private void btn_Click(object sender, EventArgs e){
// here it checks if sender is button and make the assignment, all in one shot.
// Bad readability, thus not recommended
if (!(sender is Button senderButton))
return;
var _text = senderButton.Text;
...

Problem with button when text entered into the textbox

I am trying to make the save button visible when text is entered into the text box by using the following code:
if (tbName.TextModified == true)
{
btnCTimetablesOk.Visible = true;
}
else
{
btnCTimetablesOk.Visible = false;
}
but it gives error at tbname.textmodified
is there any other way to visible the button when we enter the text in text box
this is error i am getting "the event textbox.textmodified can only appear on the left hand side of += or -="

Try using the textbox's Enter and Leave events to show/hide your button:
private void textBox1_Enter(object sender, System.EventArgs e)
{
btnCTimetablesOk.Visible = true;
}
private void textBox1_Leave(object sender, System.EventArgs e)
{
btnCTimetablesOk.Visible = false;
}
Then modify your textbox to use these new methods.

If I'm reading your text correctly, you want the save button to be visible when the textbox has text in it and invisible when the text box is blank. If that's the case, you can use the Leave event (which occurs when the textbox loses focus) and a simple if statement:
private void textBox1_Leave(object sender, System.EventArgs e)
{
if(textBox1.Text != "")
btnCTimetablesOk.Visible = true;
else
btnCTimetablesOk.Visible = false;
}
You can also put this conditional block in any other methods kicked off by events that change the text of the box.
Also, you might want to consider using Enabled instead of Visible, it'll leave the button on the form but will gray out the text and clicking will do nothing.

I'm going to take a stab in the dark here and assume that the button is related to the textbox and you probably want someone to be able to type something in the textbox then click the button. You probably don't want the user to have to type something, then tab out or click somewhere else to make the button visible then click the button.
tbName_TextChanged(object sender, EventArgs e)
{
btnCTimetablesOk.Visible = !String.IsNullOrEmpty(tbName.Text)
}
Btw you're getting that error because TextModified isn't a boolean property, it's an event, like TextChanged or Leave or Enter. You can assign an event handler to it but you can't just check it like that.
As an aside I personally hate systems hungarian for winforms controls. I'd much rather have a timetablesOkButton than a btnCTimeablesOK button. That way if you also have a timetablesNameTextBox you can see at a glance that the button and the textbox match. Of course it may not be up to you.

Making a radio button selected by default and making a textbox unable to take input in C#

I am coding in C# using Visual Studio 2010 and have a form whereby I have two radio buttons and a textbox, that is:
o Radio button 1 "Yes"
o Radio button 2 "No" Textbox here
I want the form to load with the "Yes" radio button already selected, that is:
x Radio button 1 "Yes"
o Radio button 2 "No" Textbox here (grayed out "cannot input text")
By default, the textbox should not accept input. I want it such that if a user clicks and selects radio button 2 "No", the text box is now able to accept input.
How do I achieve this?
private void rb_taxable_yes_CheckedChanged(object sender, EventArgs e)
{
}
private void rb_taxable_no_CheckedChanged(object sender, EventArgs e)
{
}
private void textBox1_TextChanged(object sender, EventArgs e)
{
}

On your Form in design mode set Enabled to False for the TextBox, and Checked to True for the first RadioButton.
Attach both radiobuttons to one event handler:
private void radioButton_CheckedChanged(object sender, EventArgs e)
{
textBox.Enabled = radioButton2.Checked;
}

Start out with textbox1.enabled = false, and use the onchecked event for the second radio button to change that. also set the first radio button to have radiobutton1.checked = true.

just choose the properties of your radio button 1
and then select the "checked" item as true
it will set as defult.
no need to code

linking to a radiobutton value, data is not binding, asp.net c#

hi i need to modify my code a little bit. i have a page with a radio button list and a textarea. the textarea is populated when a users makes a radio button selection.
also, when a user makes a radio button selection the url will hold an extention in the url to show which selection index number they have selection. (i.e. ?selected=0)
http://test.com/frm_Articles.aspx?selected=0
http://test.com/frm_Articles.aspx?selected=1
http://test.com/frm_Articles.aspx?selected=2
that way they can copy the url and reference it in other websites as a link. or place it in their favorites.
the problem is, if you grab the url and open a new browser, the page does not pass the value and databind accordingly. no radio buttons or content appear on the page.
must be the postback logic i think???
what's working:
when i launch the website the radio buttons appear and index 0 is set
when i select radio buttons the correct data displays and urls linking to radio button values display in browser (i.e. http://test.com/test.aspx?selected=2)
if i cut and paste pointer urls within the same browser then correct data is rendered
what doesn't work (everything that deal with an false PostBack):
1.when i launch website no data within the textarea apprears even though the radio button is set to 0 index and is visiable.
2. if i cut and paste pointer url into a new browser, text area and radio buttons do not display.
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack == false)
{
int selected;
if (Request.QueryString["selected"] != null)
{
if (int.TryParse(Request.QueryString["selected"], out selected))
{
RadioButtonList1.SelectedIndex = selected;
RadioButtonList1.DataBind();
}
}
else
{
int firstart = 0;
RadioButtonList1.SelectedIndex = firstart;
RadioButtonList1.DataBind();
}
}
}
protected void SqlDataSource2_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
{
//
}
protected void SqlDataSource1_Selecting(object sender, SqlDataSourceSelectingEventArgs e)
{
try{
e.Command.Parameters["#URL_FK"].Value = Session["URL_PK"];
}
catch (Exception ex)
{
}
}
protected void RadioButtonList1_SelectedIndexChanged(object sender, EventArgs e)
{
string strRedirect;
strRedirect = "test.aspx?selected=" + RadioButtonList1.SelectedIndex;
Response.Redirect(strRedirect);
}
}

In your code at Page_Load event before this line
RadioButtonList1.SelectedIndex = selected;
you should bind RadioButtonList1. after binding RadioButtonList you can set SelectedIndex.

my SqlDataSource1_Selecting method was the issue. i used another approach and my code worked.