How to save combobox values in forms - C# Discussion Boards

31-Jul-16 20:46

I have two forms form1 and form2.in form1 I have a button that opens form2.in form2 I have a combobox and button.on clicking a button in form1,form2 will be displayed,then in form 2 I will add items to comboxbox by clicking a button present in form2.on closing the form2,the values added by clicking the button disappears,so help me to come out of it.i don't want to use databases.i just want that values be binded until the close of main form Form1.
Form1.cs

private button1_click(object o,EventArgs e)
{
Form2 F2 = new Form2;
F2.Show();
}

Form2.cs
int i=0;
private void button1_Click(object sender, EventArgs e)
{
i = i + 1;

comboBox1.SelectedIndex = comboBox1.Items.Add("Message" + i);

}
help me with proper examples
The scope of saving,means values on combox box must be remained until the close of Form1.

modified 1-Aug-16 3:12am.

Richard MacCutchan31-Jul-16 21:23

Richard MacCutchan

31-Jul-16 21:23

You need to save the values somewhere so that Form2 can read them every time it starts, and save any changes when it closes. This has already been explained in your recent QA post at How do I save the values entered on the text box, list boxes in the forms[^].

OriginalGriff31-Jul-16 21:27

OriginalGriff

31-Jul-16 21:27

Since you are using Show it's a little complicated.
What you need to do is get the selection back from Form2 to Form1 and then "re-use it" next time you need Form2. That's pretty simple in theory: just write a property in Form2 which gets and sets teh information:

public int SelectedIndex
    {
    get { return comboBox1.SelectedIndex; }
    set { comboBox1.SelectedIndex = value; }
    }

And if you use ShowDialog to display Form2, it's easy:

private int index = 0;
private void button1_click(object o,EventArgs e)
    {
    Form2 F2 = new Form2();
    F2.SelectedIndex = index;
    F2.ShowDialog();
    index = F2.SelectedIndex;
    }

Or better:

private int index = 0;
private void button1_click(object o,EventArgs e)
    {
    Form2 F2 = new Form2();
    F2.SelectedIndex = index;
    if (F2.ShowDialog() == DialogResult.OK)
        {
        index = F2.SelectedIndex;
        }
    }

But with Show it's more complicated. What you need to do then is handle the FormClosed event:

private int index = 0;
private Form2 F2;
private void button2_Click(object o, EventArgs e)
    {
    F2 = new Form2();
    F2.SelectedIndex = index;
    F2.FormClosed += F2_FormClosed;
    F2.Show();
    }
private void F2_FormClosed(object sender, FormClosedEventArgs e)
    {
    index = F2.SelectedIndex;
    }

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Member 126599261-Aug-16 19:00

1-Aug-16 19:00

sorry,it hasn't helped me.any other solutions

Pete O'Hanlon1-Aug-16 20:18

1-Aug-16 20:18

As we can't see any of your code, we can't see whether or not you implemented this properly. Given OG's experience as a developer, I would expect that the problem is you haven't implemented what he told you properly.

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Member 126599261-Aug-16 20:31

1-Aug-16 20:31

hi Pete O'Hanlon,
can u provide me any working example

Pete O'Hanlon1-Aug-16 20:35

1-Aug-16 20:35

OG already has provided you with the solution. You just need to plug it into your forms. Anything I put would just be duplicating his answer.

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Member 126599261-Aug-16 22:38

1-Aug-16 22:38

here is the code that I have tried
Form1 has a single button.
Form1.cs
private int index = 0;
private void button1_Click(object sender, EventArgs e)
{

Form2 F2 = new Form2();
F2.SelectedIndex = index;
F2.ShowDialog();
index = F2.SelectedIndex;
}

Form2 has a combobox and a button
Form2.cs

int i = 0;
private void button1_Click(object sender, EventArgs e)
{
i = i + 1;
comboBox1.Items.Add("Message" + i);
}

public int SelectedIndex
{
get { return comboBox1.SelectedIndex; }
set { comboBox1.SelectedIndex = value; }
}

aboveis the code.on running the above.i clicked the button on form1 it opens form2.in form2 on cliking the button I have added items to form1.then I close the form2 and reopen it from form1 button.then also no item will be present in combobox on form2.
please let me know where I did wrong.

Pete O'Hanlon1-Aug-16 23:36

1-Aug-16 23:36

You have missed out the code to re-add items into the combo box when you show the dialog again. I also don't see you returning these added items from Form2 back to Form1 to be re-added back in.

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Member 126599261-Aug-16 23:39

1-Aug-16 23:39

how to do that,

Pete O'Hanlon1-Aug-16 23:53

1-Aug-16 23:53

In a similar way that you got the selected index. Put a couple of methods in Form2 - the first to retrieve the list of combo items and the second to set the list. In the second method, populate the combo box - call this before you call ShowDialog. It's not that hard, so I leave it to you to complete.

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Member 126599262-Aug-16 1:13