Error - There is already an open DataReader associated with Command which must be closed first

[Lin100]

When I click on listBox1, I have 2 error messages

ERROR: There is already an open DataReader associated with Command which must be closed first
        this.unitTableAdapter1.FillBy(this.dataSet_Property_Name_And_Unit_List.Unit);

ERROR: System.ArgumentNullException: 'Value cannot be null. Parameter name: key'
       catch (System.Exception ex)

///////////////////////////////////////

DataSet_Property_Name_And_Unit_List.xsd --> Right Click - -> Open --> UnitTableAdapter --> Right Click --> Configure
SELECT Property_Name, Unit_Number FROM Unit

///////////////////////////////////////

DataSet_Unit_Detail.xsd --> Right Click - -> Open --> UnitTableAdapter --> Right Click --> Configure
SELECT Unit_Number, Property_Name, Rental_Cost, Security_Deposit, Bedroom, Bathroom, Square_Feet, Status
FROM Unit WHERE (Property_Name = '@Property_Name')

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Retrieve_Data_From_Access_With_Navigation_Button
{
    public partial class Form3 : Form
    {
        public Form3()
        {
           InitializeComponent();
        }

        private void unitBindingNavigatorSaveItem_Click(object sender, EventArgs e)
        {
           this.Validate();
           this.unitBindingSource.EndEdit();
           this.tableAdapterManager.UpdateAll(this.dataSet_Unit_Detail);
        }

        private void Form3_Load(object sender, EventArgs e)
        {
ERROR: System.ArgumentNullException: 'Value cannot be null. Parameter name: key'
           this.unitTableAdapter1.Fill(this.dataSet_Property_Name_And_Unit_List.Unit);
           this.unitTableAdapter.Fill(this.dataSet_Unit_Detail.Unit);
        }

        private void fillByToolStripButton_Click(object sender, EventArgs e)
        {
            try
            {
                this.unitTableAdapter1.FillBy(this.dataSet_Property_Name_And_Unit_List.Unit);
            }
            catch (System.Exception ex)
            {
                System.Windows.Forms.MessageBox.Show(ex.Message);
            }
        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            try
            {
              ERROR BELOW: There is already an open DataReader associated with Command 
              which must be closed first
              this.unitTableAdapter1.FillBy(this.dataSet_Property_Name_And_Unit_List.Unit);
            }

            ERROR BELOW: System.ArgumentNullException: 'Value cannot be null. Parameter name: key'
            catch (System.Exception ex)
            {
                System.Windows.Forms.MessageBox.Show(ex.Message);
            }
        }
    }
}

 

 

 

Last edited: Thursday at 5:43 PM

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