How to delete selected item of listbox after click a button?

Question

I tried delete selected item of listbox after click a button.But I failed.

What is wrong in this code ?

Function for delete

public void RemoveFromList()
{
    int c = listNotMatchedItems.Items.Count - 1;
    for (int i = c; i >= 0; i++)
    {      
       listNotMatchedItems.Items.RemoveAt(i);
    }
}

Click Button

private void AddToAnotherList_Click(object sender, EventArgs e)
{
    //Add to another list.some codes....
    RemoveFromList();
}

Answer 1

Problem : your function RemoveFromList() removes all items from the ListBox.

Solution : if you want to remove the selected Item only then use ListBox1.SelectedIndex to get the Selected Item index and pass it to the ListBox1.Items.RemoveAt() method.

Try This:

private void AddToAnotherList_Click(object sender, EventArgs e)
{
   //Add to another list.some codes....
   listNotMatchedItems.Items.RemoveAt(listNotMatchedItems.SelectedIndex);
}

EDIT : in your listNotMatchedItems_SelectedIndexChanged event handler

Replace This:

string table = listNotMatchedItems.SelectedItem.ToString();

With This:

private void listNotMatchedItems_SelectedIndexChanged(object sender, EventArgs e)
    {
       string table =String.Empty;
       if(listNotMatchedItems.SelectedItems.Count>0)   
       {  
         using (SqlConnection con = new SqlConnection(strConnectDB1))
         {
            con.Open();


               using (SqlCommand comQuery = new SqlCommand(@" declare @vsSQL varchar(8000)
               declare @vsTableName varchar(50)
               select @vsTableName = @TT
               select @vsSQL = 'CREATE TABLE ' + @vsTableName + char(10) + '(' + char(10)
               select @vsSQL = @vsSQL + ' ' + sc.Name + ' ' +
               st.Name +
               case when st.Name in ('varchar','varchar','char','nchar') then '(' + cast(sc.Length as varchar) + ') ' else ' ' end +
               case when sc.IsNullable = 1 then 'NULL' else 'NOT NULL' end + ',' + char(10)
               from sysobjects so
               join syscolumns sc on sc.id = so.id
               join systypes st on st.xusertype = sc.xusertype
               where so.name = @vsTableName
               order by
               sc.ColID
               select substring(@vsSQL,1,len(@vsSQL) - 2) + char(10) + ')'", con))

           {

              comQuery.Parameters.AddWithValue("@TT", listNotMatchedItems.SelectedItem);

                using (SqlDataReader readerQuery = comQuery.ExecuteReader())

                {

                    txtNotMachedQuery.Text = "";
                    int a = 0;

                    while (readerQuery.Read())
                    {
                        a++;
                      txtNotMachedQuery.Text = readerQuery[0].ToString() ;


                    }



                }


            }




            using (SqlCommand com = new SqlCommand(@"SELECT * FROM " + table, con))
            {



                using (SqlDataReader reader = com.ExecuteReader(CommandBehavior.SchemaOnly))
                {
                    listNotMachedFields.Items.Clear();
                    DataTable schemaTable = reader.GetSchemaTable();
                    foreach (DataRow colRow in schemaTable.Rows)
                        listNotMachedFields.Items.Add(colRow.Field<String>("ColumnName"));



                   }

               }
             }
            }//if end
        }

EDIT 2:

Replace This:

comQuery.Parameters.AddWithValue("@TT", listNotMatchedItems.SelectedItem);

With This:

comQuery.Parameters.AddWithValue("@TT", listNotMatchedItems.SelectedValue.ToString());