CODEWITHSUNDEEP
c#wpfxaml
kar
kar

Reputation: 3651

ComboBox selection returning IndexOutofBounds Error

I am setting up such that the choice of my first combobox(name = combo3) determines what the second combobox(name = combo4) will show. This works fine.

Now I am trying to make the second combobox determine what my third combobox will show. This doesn't work. The moment I make a selection on the second combox, it jams and returns error. But if I hard code the value of the 2nd combobox, it works.

I am getting indexoutofbounds exception. Problem seems to be with the method private void ComboBox_SelectionChanged2(). Please advice what is wrong. Thanks.

MainWindow

string[] tableArray = { "Agent_Name", "Agent_Age", "Agent_Gender", "Agent_Alias", "Security_Clearance", "Dept_ID", "Job_ID", "Mission_ID" };
string[] attributeArray = { "Mission_Name", "Mission_Description", "Mission_Country", "Mission_City" };

private void ComboBox_SelectionChanged1(object sender, SelectionChangedEventArgs e)  
        {
            if (((ComboBoxItem)combo3.SelectedItem).Content.ToString() == "Agents")
            {
                combo4.Items.Clear();
                foreach (string x in tableArray)
                {
                    combo4.Items.Add(x);
                }
            }
            else
            {
                combo4.Items.Clear();
                foreach (string x in attributeArray)
                {
                    combo4.Items.Add(x);
                }
            }
        }

private void ComboBox_SelectionChanged2(object sender, SelectionChangedEventArgs e)
        {
            combo5.Items.Clear();
            MessageBox.Show(combo4.Text); //debugging line returns empty which shouldn't be the case. I chose Mission_Name thus it should show Mission_Name. 
            //fillCombo("SELECT * FROM " + combo3.Text + ";", "Mission_Name", combo5); //works   
            fillCombo("SELECT * FROM " + combo3.Text + ";", combo4.Text, combo5); // not working
        } 

private void fillCombo(string query, string name, ComboBox c)
        {
            MySqlCommand cmdReader = new MySqlCommand(query, conn);
            MySqlDataReader myReader;

            myReader = cmdReader.ExecuteReader();

            while (myReader.Read())
            {
                string temp = myReader.GetString(name);
                c.Items.Add(temp);
            }
            myReader.Close();
        }

XAML:

<ComboBox x:Name="combo3" Width="120" SelectionChanged="ComboBox_SelectionChanged1">
                <ComboBoxItem x:Name="box3" Content="Agents"/>
                <ComboBoxItem x:Name="box4" Content="Missions"/>
            </ComboBox>
            <ComboBox x:Name="combo4" Width="120" SelectionChanged="ComboBox_SelectionChanged2">
            </ComboBox>
<ComboBox x:Name="combo5" Width="120" Canvas.Left="818" Canvas.Top="588"/>

Error Message:

An unhandled exception of type 'System.IndexOutOfRangeException' occurred in MySql.Data.dll

Additional information: Could not find specified column in results:

How the combo boxes looks.

enter image description here

Upvotes: 0

Views: 361

Answers (4)

kpal
kpal

Reputation: 1

Check for e.AddedItems.Count > 0 in SelectionChanged.

Upvotes: 0

csharpwinphonexaml
csharpwinphonexaml

Reputation: 3683

Replace this

MessageBox.Show(combo4.Text);

With this:

MessageBox.Show(combo4.SelectedText);

Or with this:

MessageBox.Show(combo4.SelectedItem.ToString());

replace everywhere you use combo4.Text as-well as combo1 2 3 and so on

Upvotes: 1

Chris Barlow
Chris Barlow

Reputation: 3314

The problem is that you are using the ComboBox_SelectionChanged2 event to run the code to fill out your comboboxes, but you aren't validating that the comboboxes have selections made before running the code. This event will be triggered when the combobox is painted on the form with no value selected in some of the other comboboxes. You just need to put a conditional in your event that ensures that your comboboxes have values before trying to access them.

private void ComboBox_SelectionChanged2(object sender, SelectionChangedEventArgs e)
    {
        if (combo3.Text.Length > 0 && combo4.Text.Length > 0)
        {
           combo5.Items.Clear();
           MessageBox.Show(combo4.Text); //debugging line returns empty which shouldn't be the case. I chose Mission_Name thus it should show Mission_Name. 
           //fillCombo("SELECT * FROM " + combo3.Text + ";", "Mission_Name", combo5); //works   
           fillCombo("SELECT * FROM " + combo3.Text + ";", combo4.Text, combo5); // not working
        }
    }

Upvotes: 0

Yuval Itzchakov
Yuval Itzchakov

Reputation: 149538

As i said in the comments, there is a problem with the string being generated to query that database.

Try debugging your application and set a breakpoint to your combobox4.Text property and see what it generates.

Upvotes: 0

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