Question

I have a list box on my WinForms application which populates with the following SQL code in C#:

 private void PopulateClients()
    {
        string sqlText = "SELECT ClientID, ClientName FROM tblClients;";
        cSqlQuery cS = new cSqlQuery(sqlText, "table");
        lbxClient.DataSource = cS.cTableResults;
        lbxClient.DisplayMember = "ClientName";
        lbxClient.ValueMember = "ClientID";
    }

So whilst the list box displays client names, the value it should return when selected is the numerical clientID.

However, later in the code –

 private void btnAddNewJob_Click(object sender, EventArgs e)
    {
        try
        {
            string strNewJobName = txtNewJobName.Text;
            string strNewJobRef = txtNewJobRef.Text;
            int intNewJobClient = (int)lbxClient.SelectedValue;
            string sqlText = "INSERT INTO tblJobs (JobID, JobClient, JobRef, JobName) " +
                             "VALUES (@JobID, @JobClient, @JobRef, @JobName);";
            SqlCommand sqlCom = new SqlCommand(sqlText);
            sqlCom.Parameters.Add("@JobID", SqlDbType.Int);
            sqlCom.Parameters.Add("@JobClient", SqlDbType.Int);
            sqlCom.Parameters.Add("@JobRef", SqlDbType.Text);
            sqlCom.Parameters.Add("@JobName", SqlDbType.Text);
            cConnectionString cS = new cConnectionString();
            sqlCom.Parameters["@JobID"].Value = cS.NextID("JobID", "tblJobs");
            sqlCom.Parameters["@JobClient"].Value = intNewJobClient;
            sqlCom.Parameters["@JobRef"].Value = strNewJobRef;
            sqlCom.Parameters["@JobName"].Value = strNewJobName;
            cSqlQuery cQ = new cSqlQuery(sqlCom, "non query");
            PopulateJobs();
            txtNewJobName.Text = "";
            txtNewJobRef.Text = "";
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

Fails on the third line

int intNewJobClient = (int)lbxClient.SelectedValue;

With an invalid cast. As far as I can see the listbox is still returning the Client Name, whereas it should be returning then numerical clientID (int).

Any ideas?

Answer 1

In the end I had to do this:

int intClient = 0;
        try
        {
            intClient = (int)lbxClient.SelectedValue;
        }
        catch (Exception)
        {
            intClient = 0;
        }

Which I feel like is a bit of a fudge – but it works!