How to get id of selected item in combobox C#

Question

5.00/5 (1 vote)

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Hi, i am working with combobox in my windowsForm project.
I get an attribute "LIB" from sql server table value showed in the combobox.
I need to get another attribute "GUID" of the selectedItem and pass it from the first Form (FormMaster) to another Form (FormImport).

What I have tried:

C#

int ScénarioIndex = comboBox3.SelectedIndex;                     
             SqlCommand cmd = new SqlCommand("SELECT [OID] FROM [AffecAnalytique].[dbo].[DESCRIPTIF] WHERE [LIBELLE]='" + comboBox3.Items[ScénarioIndex] + "' ", con);
             con.Open();
             SqlDataReader rdr = cmd.ExecuteReader();
             if (rdr.HasRows)
             {
                 string strOIDe = (string)rdr["OID"];
                 MessageBox.Show(strOIDe,"OID"); 
             }
             con.Close();

Posted 29-Sep-20 23:58pm

houssem eddine ayari

Updated 30-Sep-20 5:40am

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Comments

Richard MacCutchan 30-Sep-20 6:13am

Where is the GUID, in the ComboBox or the database?

houssem eddine ayari 30-Sep-20 8:32am

In the database

Richard Deeming 30-Sep-20 7:10am

SqlCommand cmd = new SqlCommand("SELECT [OID] FROM [AffecAnalytique].[dbo].[DESCRIPTIF] WHERE [LIBELLE]='" + comboBox3.Items[ScénarioIndex] + "' ", con);

Your code is vulnerable to SQL Injection[^]. NEVER use string concatenation to build a SQL query. ALWAYS use a parameterized query.

Everything you wanted to know about SQL injection (but were afraid to ask) | Troy Hunt[^]
How can I explain SQL injection without technical jargon? | Information Security Stack Exchange[^]
Query Parameterization Cheat Sheet | OWASP[^]

using (SqlCommand cmd = new SqlCommand("SELECT [OID] FROM [AffecAnalytique].[dbo].[DESCRIPTIF] WHERE [LIBELLE] = @LIBELLE", con))
{
    cmd.Parameters.AddWithValue("@LIBELLE", comboBox3.Items[ScénarioIndex]);
    
    con.Open();
    object result = cmd.ExecuteScalar();
    if (result != null && !Convert.IsDBNull(result))
    {
        string strOIDe = (string)result;
        MessageBox.Show(strOIDe,"OID"); 
    }
}

houssem eddine ayari 30-Sep-20 8:38am

Nothing is returned. Not even an empty messagebox

Richard Deeming 30-Sep-20 10:58am

Then there is no matching record in your database.

houssem eddine ayari 30-Sep-20 11:28am

The value LIBELLE selected with combobox exists in my database. I just updated my code to show a messagebox inside the if condition and nothing was showed.

Richard MacCutchan 30-Sep-20 11:57am

Use your debugger to examine the SQL string to ensure that it is passing valid data.

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Gerry Schmitz · Accepted Answer · 2020-09-30T05:41:00

Solution 1

Your current binding is too simplistic. The following pattern is more useful for many situations, including your current one.

Get Selected Text and Value of ComboBox in Windows Application using C# and VB.Net[^]

Posted 30-Sep-20 5:41am

Gerry Schmitz

Comments

houssem eddine ayari 1-Oct-20 5:17am

I just have a question: how can I add a static text to the DisplayMember. comboBox3.DisplayMember ="LIBELLE"; --> get the data from DB.
I want the data to be showen in my combobox like this --> Scenario: LIBELLE