I am able to bind the data from database to a ComboBox
, but while trying to save selected index value back, it shows a null reference error
.
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
BindPAId();
getPartyAccType();
}
private void btnAdd_Click(object sender, EventArgs e)
{
mode = "New";
// getting error here
string AccTypeIndex = ddlAccountType.SelectedIndex.ToString();
}
public void getPartyAccType()
{
// ddlAccountType.Items.Clear();
PartyAccount objType = new PartyAccount();
List<PartyAccount> ListType = objType.getAccountPartyType();
ddlAccountType.DataSource = ListType;
ddlAccountType.ValueMember = "AccTypeId";
ddlAccountType.DisplayMember = "AccType";
ddlAccountType = null;
ListType = null;
}
The reason you are getting a NullReferenceException
is because you set the reference to null
yourself. The problem lies within your getPartyAccType
:
public void getPartyAccType()
{
PartyAccount account = new PartyAccount();
List<PartyAccount> accountPartyType = account.getAccountPartyType();
ddlAccountType.DataSource = accountPartyType;
ddlAccountType.ValueMember = "AccTypeId";
ddlAccountType.DisplayMember = "AccType";
//ddlAccountType = null;
//accountPartyType = null;
}
There is no need to null
the dllAccountType
whatsoever. Nulling this means completely removing the reference to your component, which is not what you want. Also, you don't need to null
the accountPartyType
( ListType
in your code) variable, the .NET garbage collector will remove the object from memory if needed; there is no need to do this yourself.
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