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i have a problem in desktop Application when i want to add a New Store
first Error
System.InvalidOperationException: 'Cannot attach an entity that already exists.'

Second Error
System.Data.SqlClient.SqlException: 'Cannot insert explicit value for identity column in table 'Store' when IDENTITY_INSERT is set to OFF.'

What I have tried:

C#
public partial class Store : DevExpress.XtraEditors.XtraForm
{
    DAL.Store store;
    public Store()
    {
        InitializeComponent();
        AddNew();
    }

    private void Store_Load(object sender, EventArgs e)
    {
       
    }

    void Save()
    {
        if (txtStore.Text.Trim()==string.Empty)
        {
            MessageBox.Show("Enter Store Name");
            return;
        }


        DAL.dbDataContext db = new DAL.dbDataContext();
        if(store.id==0)
        {
            store.id = 1;
            db.Stores.InsertOnSubmit(store);
        }
        
           db.Stores.Attach(store);
            UpdateData();
            db.SubmitChanges();
    }

    void GetData()
    {
        txtStore.Text = store.Store_Name;

    }
    void UpdateData()
    {
        store.Store_Name = txtStore.Text;

    }

    void AddNew()
    {
        store = new DAL.Store();
        GetData();
        

    }

    private void SaveBtn_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
    {
        Save();
    }

    private void NewBtn_ItemClick(object sender, DevExpress.XtraBars.ItemClickEventArgs e)
    {
        AddNew();
        
    }
}
Posted
Updated 7-Dec-20 1:10am
v2
Comments
Gerry Schmitz 5-Dec-20 15:21pm
   
You're inserting and attaching at the same time.
ahmedbelal 5-Dec-20 17:03pm
   
OH ! yes Ok What's the Solution ??
BabyYoda 7-Dec-20 9:18am
   
Don't attach when it already exists. Isn't that what you error says?

The second one is also clear. You can't insert into an identity column when IDENTITY_INSERT is off.

Not to be rude, but you need to do some very basic learning. These are very simple problems if you understand how code works.

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