How to retrieve selected Combo Box item in User Control Page

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How to retrieve selected Combo Box item in User Control Page
Combo Box Control is in Main Window.Upon Selection User Control will be loaded with selected values
how to achieve this?

Posted 16-Nov-15 18:33pm

mithun286

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PANKAJMAURYA · Accepted Answer · 2015-11-16T18:42:00

Solution 1

You can try this. Not tested

C#

Window parentWindow = Window.GetWindow(this);
ComboBox cmb = parentWindow.Controls["ComboBoxID"] as ComboBox;

Now You can get the value

C#

string val = cmb.Text;

OR

C#

ComboBoxItem cmbItem= cmb.SelectedItem as ComboBoxItem;
string val = cmbItem.Content.ToString();

Posted 16-Nov-15 18:42pm

PANKAJMAURYA

Updated 16-Nov-15 20:01pm

v4

Comments

mithun286 17-Nov-15 0:53am

This are the errors i am getting:

Error 2 'WpfApplication1.WindowDropDownMap' does not contain a definition for 'Controls' and no extension method 'Controls' accepting a first argument of type 'WpfApplication1.WindowDropDownMap' could be found (are you missing a using directive or an assembly reference?) C:\Users\Mithun\Downloads\wpfApplication\WpfApplication1\WpfApplication1\UserControlMap.xaml.cs 43 39 WpfApplication1

Error 3 Cannot implicitly convert type 'object' to 'string'. An explicit conversion exists (are you missing a cast?) C:\Users\Mithun\Downloads\wpfApplication\WpfApplication1\WpfApplication1\UserControlMap.xaml.cs 44 26 WpfApplication1

[no name] 17-Nov-15 1:04am

Try now. Updated the solution according to your application.

mithun286 17-Nov-15 0:59am

private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
WindowDropDownMap control = new WindowDropDownMap();

WindowDropDownMap parentForm = this.Parent as WindowDropDownMap;
ComboBox cmb = parentForm.Controls["selectOption"] as ComboBox;
string val =cmb.SelectedValue;
}

This is the way i used your code
please correct if i am wrong

[no name] 17-Nov-15 1:03am

Use this code in your UserControl_Loaded event
Window parentWindow = Window.GetWindow(this);
ComboBox cmb = parentWindow.Controls["ComboBoxID"] as ComboBox;
string val = Convert.ToString(cmb.SelectedValue);

mithun286 17-Nov-15 1:18am

My Window name is
WindowDropDownMap
and i am getting error near Controls
Do not have the definition for Controls

[no name] 17-Nov-15 1:29am

Window parentWindow = Window.GetWindow(this);
ComboBox cmb = parentWindow.FindName("ComboBoxID") as ComboBox;
string val = Convert.ToString(cmb.SelectedValue);

mithun286 17-Nov-15 1:35am

at this line of code:string val = Convert.ToString(cmb.SelectedValue);
there is run time error ie.
A first chance exception of type 'System.NullReferenceException' occurred in WpfApplication1.exe

Additional information: Object reference not set to an instance of an object.

mithun286 17-Nov-15 1:38am

Sorry i Corrected it.
But Though i select the value in drop down i am getting empty in return

mithun286 17-Nov-15 1:40am

This is My DropDown Code:
<combobox horizontalalignment="Left" margin="169,30,0,0" verticalalignment="Top" width="201" name="selectOption" selectionchanged="ComboBox_SelectionChanged">
<comboboxitem content="13.017063">
<comboboxitem content="13.017564">
<comboboxitem content="12.989084">
<comboboxitem content="12.989313">

This is User Control onLoad Code:

private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
WindowDropDownMap control = new WindowDropDownMap();

WindowDropDownMap window = new WindowDropDownMap();
window.Owner = Window.GetWindow(this);
ComboBox cmb = window.FindName("selectOption") as ComboBox;
var val = Convert.ToString(cmb.SelectedValue);
}

[no name] 17-Nov-15 1:58am

var val = cmb.Text;

mithun286 17-Nov-15 1:42am

cmb.SelectedValue = null i am getting

[no name] 17-Nov-15 2:01am

use
var val = cmb.Text;

mithun286 17-Nov-15 2:07am

I tried that still it is Empty only.

[no name] 17-Nov-15 2:08am

Try

ComboBoxItem cmbItem= cmb.SelectedItem as ComboBoxItem;
string val = cmbItem.Content.ToString();

mithun286 17-Nov-15 2:13am

Error at this line
string val = cmbItem.Content.ToString();
Additional information: Object reference not set to an instance of an object.

This is my entire code
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{

WindowDropDownMap window = new WindowDropDownMap();
window.Owner = Window.GetWindow(this);
ComboBox cmb = window.FindName("selectOption") as ComboBox;
ComboBoxItem cmbItem = cmb.SelectedItem as ComboBoxItem;
string val = cmbItem.Content.ToString();
}

[no name] 17-Nov-15 2:15am

ComboBoxItem cmbItem = cmb.SelectedItem as ComboBoxItem;
if(!Equals(cmbItem,null))
{
string val = cmbItem.Content.ToString();
}

mithun286 17-Nov-15 2:18am

It is not going inside if condition.
But there are values inside drop down

mithun286 17-Nov-15 2:28am

WindowDropDownMap window = new WindowDropDownMap();
window.Owner = Window.GetWindow(this);
ComboBox cmb = window.FindName("selectOption") as ComboBox;
ComboBoxItem cmbItem = cmb.SelectedItem as ComboBoxItem;
if (!Equals(cmbItem, null))
{
string val = cmbItem.Content.ToString();
}
this is how i implemented.

mithun286 17-Nov-15 4:05am

Can u help me?

[no name] 17-Nov-15 4:07am

need to debug the issue why SelectedItem is null in your case. Debug the issue and see the combobox in quick wath and try to get SelectedItem.

mithun286 17-Nov-15 5:13am

When i check with quick watch
{System.Windows.Controls.ComboBox Items.Count:4}

does this mean i have data?

Because count is correct. i Only have 4 items in Combo Box Control

[no name] 17-Nov-15 5:16am

try to figure it out in quick watch what is Combobox.SelectedItem give.

mithun286 17-Nov-15 5:17am

It is Giving null :(

mithun286 17-Nov-15 5:19am

What else is the solution for this?

[no name] 17-Nov-15 5:28am

Alternative solution for this is make a static property in your user control class and assign its value in combobox selectedindexchanged event . Now get it in your user control class

mithun286 17-Nov-15 5:38am

what are the changes in usercontrol and main window where dropdown is located

[no name] 17-Nov-15 5:44am

Write this in WindowDropDownMap

public static string CMBSelectedValue {get;set;}

On SelectedIndexChanged event assign value
WindowDropDownMap.CMBSelectedValue = selectOption.SelectedValue;
Now trying to get value in User Control like
string str = WindowDropDownMap.CMBSelectedValue;

mithun286 17-Nov-15 5:55am

String value i am getting like:
System.Windows.Controls.ComboBoxItem: 13.017063

How to get only 13.017063?

[no name] 17-Nov-15 6:06am

Use
WindowDropDownMap.CMBSelectedValue = selectOption.SelectedItem.Content.ToString();

mithun286 17-Nov-15 6:11am

Does not Contain the Definition for Content is the error i am getting :(
please help

mithun286 17-Nov-15 6:12am

'object' does not contain a definition for 'Content' and no extension method 'Content' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)

This Error i am Getting.

[no name] 17-Nov-15 6:20am

Try
WindowDropDownMap.CMBSelectedValue = ((ComboBoxItem)selectOption.SelectedItem).Content.ToString();

mithun286 17-Nov-15 6:25am

Thanks a lot !!!!
Problem Solved :)

But have one more issue please go through it:
Can we have two values in one comboBox like
13.017063,77.484069
and retrieve those values separately ?
can u help me in this ?

[no name] 17-Nov-15 6:27am

No you cant not get value seperatly. you will get the value in a single string and need to split it by ',' that will give an string array of two values and use accordingly.

mithun286 17-Nov-15 6:33am

How to split it and make 2 strings can you tell me through code?

[no name] 17-Nov-15 6:35am

string[] str = WindowDropDownMap.CMBSelectedValue.Split(',');

Now str[0] will give first value and str[1] will give 2nd value.

mithun286 17-Nov-15 6:46am

It is working but at initial stage there is a error in user control load ie
Additional information: Object reference not set to an instance of an object. at this line
string[] str = WindowDropDownMap.CMBFirstValue.Split(',');

[no name] 17-Nov-15 6:59am

try to put it in
if(!string.IsNullOrEmpty(WindowDropDownMap.CMBFirstValue))
{
string[] str = WindowDropDownMap.CMBFirstValue.Split(',');
}

mithun286 17-Nov-15 7:17am

Thanks a lot
Problem solved!!!! :)

mithun286 17-Nov-15 6:34am

It will solve my entire problem!!!

[no name] 17-Nov-15 6:30am

Please mark the solution as answer that will guide others to solve same problem.

mithun286 17-Nov-15 5:31am

Can u give me a coding example for this explanation?

PANKAJMAURYA · Accepted Answer · 2015-11-17T00:29:00

Write this in your WindowDropDownMap class

C#

public static string CMBSelectedValue {get;set;}

On SelectedIndexChanged event assign value

C#

WindowDropDownMap.CMBSelectedValue = ((ComboBoxItem)selectOption.SelectedItem).Content.ToString();

Now trying to get value in User Control like

C#

string str = WindowDropDownMap.CMBSelectedValue;

mithun286 · Accepted Answer · 2015-11-16T19:47:00

XML

<ComboBox HorizontalAlignment="Left" Margin="169,30,0,0" VerticalAlignment="Top" Width="201" Name="selectOption" SelectionChanged="ComboBox_SelectionChanged">
         <ComboBoxItem Content="13.017063"/>
         <ComboBoxItem Content="13.017564"/>
         <ComboBoxItem Content="12.989084"/>
         <ComboBoxItem Content="12.989313"/>
     </ComboBox>

Drop Down Code

How to retrieve selected Combo Box item in User Control Page

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