How to create PK identity in temporary DataTable?

Question

How to create PK identity in temporary DataTable?

Navigation

#1 by (2 votes)

2

I'm working on a Windows Forms app, Visual Studio 2015. The scenario is that I have a DataGridView where I will enter items to a Detail, I will enter data from a product of a range of sizes that are worth a price, and the same product I will enter it with another range of sizes that are worth another price, so I need to enter the same product more than once.

For this I have implemented a temporary DataTable given the code:

public class DetalleCompraRepository
{
    private DataTable _detalleTemp = new DataTable();
    public DetalleCompraRepository()
    {
        _detalleTemp = new DataTable("_detalleTemp");
        DataColumn colId = new DataColumn();
        colId.DataType = System.Type.GetType("System.Int32");
        colId.AutoIncrement = true;
        colId.AutoIncrementSeed = 1;
        colId.AutoIncrementStep = 1;
        _detalleTemp.Columns.Add("colId", typeof(int));
        _detalleTemp.PrimaryKey = new DataColumn[] { _detalleTemp.Columns[0] };

        _detalleTemp.Columns.Add("ProductoId", typeof(int));
        _detalleTemp.Columns.Add("Descripcion", typeof(string));
        _detalleTemp.Columns.Add("Cantidad", typeof(int));
        _detalleTemp.Columns.Add("Precio", typeof(decimal));
        _detalleTemp.Columns.Add("Importe", typeof(decimal), "(Precio * Cantidad)");
    }

    public DataTable PDetalleTemp
    {
        get { return _detalleTemp; }
    }

    public void Agregar(DetalleCompra entity)
    {
        var fila = _detalleTemp.Rows.Find(entity.DetalleCompraId);
        if (fila == null)
        {
            fila = _detalleTemp.NewRow();
            fila["colId"] = entity.DetalleCompraId;
            fila["ProductoId"] = entity.ProductoId;
            fila["Descripcion"] = entity.Descripcion;
            fila["Cantidad"] = entity.Cantidad;
            fila["Precio"] = entity.Precio;
            fila["Importe"] = entity.Total;
            _detalleTemp.Rows.Add((fila));
        }
    }
}

The DataTable asks me for a pk, which I put it on but, it does not allow me to enter the same id, so I need to put a pk identity to allow me to enter the same item. I've tried this part of code:

DataColumn colId = new DataColumn();
        colId.DataType = System.Type.GetType("System.Int32");
        colId.AutoIncrement = true;
        colId.AutoIncrementSeed = 1;
        colId.AutoIncrementStep = 1;
        _detalleTemp.Columns.Add("colId", typeof(int));
        _detalleTemp.PrimaryKey = new DataColumn[] { _detalleTemp.Columns[0] };

If I can enter a first item, but when I try to enter a second item, in the Add method, you no longer enter the condition if (fila == null) and that indicates which row is not null.

The way I add the items is as follows:

private void button1_Click(object sender, EventArgs e)
    {
        var entity = new DetalleCompra()
        {
            ProductoId = Convert.ToInt32(txtProductoId.Text),
            Descripcion = txtDescripcion.Text,
            Cantidad = Convert.ToInt32(txtCantidad.Text),
            Precio = Convert.ToDecimal(txtPrecio.Text)
        };
        _detalleCompra.Agregar(entity);
        dgvDetalle.AutoGenerateColumns = false;
        dgvDetalle.DataSource = _detalleCompra.PDetalleTemp;
    }

What I need to know is:

If the implementation of creating a pk identity is correct or is there some other way to do it?

Does the DataTable have to store all the items that I enter, I mean that the row is not null, when I intend to enter a second item?

c# windows-forms visual-studio-2015

asked by Pedro Ávila 12.08.2016 в 18:08

source

1 answer

Django - Modify widget Select custom list? Place message of "No records exist" in statement prepared using search filter

score 2 · Accepted Answer

I managed to solve it, in the Click event I use Random which generates me numeric ids and I can send it to the add method through the DetalleCompraId property that is in the repository. Click event

private void button1_Click(object sender, EventArgs e)
    {
        Random rdn = new Random();
        int valor = rdn.Next();

        var entity = new DetalleCompra
        {
            DetalleCompraId = valor,
            ProductoId = Convert.ToInt32(txtProductoId.Text),
            Descripcion = txtDescripcion.Text,
            Cantidad = Convert.ToInt32(txtCantidad.Text),
            Precio = Convert.ToDecimal(txtPrecio.Text)
        };

        _detalleCompra.Agregar(entity);
        dgvDetalle.AutoGenerateColumns = false;
        dgvDetalle.DataSource = _detalleCompra.PDetalleTemp;
    }

Also modify the repository

public DetalleCompraRepository()
    {
        _detalleTemp = new DataTable("_detalleTemp");
        DataColumn colId = _detalleTemp.Columns.Add("ID", typeof (int));
        _detalleTemp.PrimaryKey = new DataColumn[] { _detalleTemp.Columns[0] };
        _detalleTemp.Columns.Add("ProductoId", typeof(int));
        _detalleTemp.Columns.Add("Descripcion", typeof(string));
        _detalleTemp.Columns.Add("Cantidad", typeof(int));
        _detalleTemp.Columns.Add("Precio", typeof(decimal));
        _detalleTemp.Columns.Add("Importe", typeof(decimal), "(Precio * Cantidad)");
    }

public void Agregar(DetalleCompra entity)
    {
        var fila = _detalleTemp.Rows.Find(entity.DetalleCompraId);
        if (fila == null)
        {
            fila = _detalleTemp.NewRow();
            fila["ID"] = entity.DetalleCompraId;
            fila["ProductoId"] = entity.ProductoId;
            fila["Descripcion"] = entity.Descripcion;
            fila["Cantidad"] = entity.Cantidad;
            fila["Precio"] = entity.Precio;
            fila["Importe"] = entity.Total;
            _detalleTemp.Rows.Add((fila));
        }
    }