Format Exception error
<p>I have a function like this</p>

<p>/// 
        /// This function binds the emplist drop down for mentor user.
        /// </p>

<pre><code>    private void BindEmpDropDownForMentor()

    {

        string strSelectMentorQuery = "SELECT FIRST_NAME + ' ' + LAST_NAME AS NAME FROM M_USER_DETAILS MUD INNER JOIN M_LEADERLED MLL "
               + "ON MLL.LED_ID = MUD.PK_ID WHERE MLL.LEADER_ID = '" + Session["UserID"].ToString()
               + "' AND MUD.ACTIVE = 1 AND MLL.START_DATE &lt;= Getdate() AND"
               + " MLL.END_DATE &gt; Getdate()";

        OleDbConnection oleConnection = new OleDbConnection(ConfigurationSettings.AppSettings["SQLConnectionString"]);
        OleDbCommand oleCommand = new OleDbCommand(strSelectMentorQuery, oleConnection);

        try
        {
            //Open Connection
            oleConnection.Open();

            //Set Datasource and close connection   
            cmbempList.DataSource = oleCommand.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
            cmbempList.DataValueField = "";
            cmbempList.DataTextField = "NAME";

            //Bind the Dropdown
            cmbempList.DataBind();

            //Add a new item 'ALL TEAM MEMBERS' to the member list
            cmbempList.Items.Insert(0, new ListItem("ALL TEAM MEMBERS", "0"));
            cmbempList.SelectedIndex = 0;

            GridViewDataShowBy = cmbempList.SelectedValue;

        }
        catch (Exception ex)
        {
            ExceptionLogger.LogException(ex);
        }
        finally
        {
            // Close the connection when done with it.
            oleConnection.Close();
        }

    }
</code></pre>

<p>But on selected change event of cmbempList, format exception error is being caught saying this that input string was not in correct form in the bold line below</p>

<p>protected void cmbempList_SelectedIndexChanged(object sender, EventArgs e)</p>

<pre><code>    {

        gvLeaveList.CurrentPageIndex = 0;
        dgDaysAbsent.CurrentPageIndex = 0;

        **if (!(Convert.ToInt32(cmbempList.SelectedValue) &gt; 0))
        {**
            if (this.Session["RoleID"].ToString() == "1")
            {
                cmbLeads.ClearSelection();
                cmbLeads.SelectedIndex = cmbLeads.Items.IndexOf(cmbLeads.Items.FindByValue(this.Session["UserID"].ToString()));
            }
        }

        GridViewDataShowBy = cmbempList.SelectedValue.ToString();

        if (cmbempList.SelectedValue != "0" &amp;&amp; cmbempList.SelectedValue != "")
        {
            Page.Title = cmbempList.SelectedItem.Text + " | Leave List | "
                       + OrganizationManager.GetCurrentOrganizationName(Session["OrgID"]);
        }
        else
        {
            Page.Title = "Leave List | "
                       + OrganizationManager.GetCurrentOrganizationName(Session["OrgID"]);
        }

        PopulateLeaveList(GridViewDataShowBy, "0");
        BindLeaveListGrid(GridViewDataShowBy, cmbLeads.SelectedValue.ToString());
    }
</code></pre>
