How can Add items to Binded Datasource Combo Box? - winforms

Question

Hi I am new to C#. I have tried following way to add new item to my bound ComboBox but it won't give any result.
Is it possible to add new item to bound ComboBox (Here Problem is ID is Bigint data type but I want to add Select ID)?
If it is possible, please provide piece of code
try
{
objSqlExecute.OpenConnection();
string strQuery = objQueryManager.GetEmployeeRecords();
//Add Extra Items to combo Box
cmbEmployeeID.Items.Add("Select Id");
DataTable dtEmployee = objSqlExecute.GetRecordExecution(strQuery);
// DataRow dtNew = dtEmployee.NewRow();
// dtNew["ID"] = "Select ID";
// dtNew["FName"] = "";
//dtEmployee.Rows.InsertAt(dtNew, 0);
cmbEmployeeID.DataSource = dtEmployee;
cmbEmployeeID.DisplayMember = "ID";
cmbEmployeeID.ValueMember = "FName";
}

Answer 1

try
{
objSqlExecute.OpenConnection();
string strQuery = objQueryManager.GetEmployeeRecords();
//Add Extra Items to combo Box
DataTable dtEmployee = objSqlExecute.GetRecordExecution(strQuery);
cmbEmployeeID.DataSource = dtEmployee;
cmbEmployeeID.DisplayMember = "ID";
cmbEmployeeID.ValueMember = "FName";
cmbEmployeeID.Items.Insert(0, "None Selected");
}

Answer 2

Did you try your query to make sure it returns values? returning multiple records, single or none?
Do you want to add ONE new item at random intervals?
Or else do you have an option to INSERT all items at once?
Can you try adding toString() for converting BigInt?
Notes:
The arcticle here gives an insight to add a new item to a combobox using sql.
Looking at the questions you are posting, to see a sample of how to use ListItems in this scenario, you could refer to the web link.