Visual Basic.NET - Rutina solo me funciona fecha del dia

Imports MySql.Data

Imports MySql.Data.Types

Imports MySql.Data.MySqlClient

Imports System.Globalization

Public Class VerFactura

    Private fechac As String

    Private Sub VerFactura_Load(sender As Object, e As EventArgs) Handles MyBase.Load

        fechac = Format(fecha_consulta.Value.Date, "yyyy-MM-dd")

        Dim conexion As MySqlConnection = New MySqlConnection

        Dim comando As MySqlCommand = New MySqlCommand

        comando.Connection = conexion

        Try

            conexion.ConnectionString = "Server=localhost;Port=3306;Database=Ventas;Uid=root;Pwd=1234;"

        Catch ex As Exception

            MsgBox(ex.Message)

        End Try

        comando.CommandText = "SELECT p_fecha as Fecha, p_hora AS Hora, p_nrot as Factura, estatus AS Estatus,

                               SUM(p_monto) AS Total FROM tbl_Facturas 

                               WHERE p_fecha = '" & fechac & "'

                               GROUP by p_fecha, p_nrot"

        Dim dt As DataTable = New DataTable

        Dim daa As MySqlDataAdapter = New MySqlDataAdapter(comando)

        daa.Fill(dt)

        DataGridViewX1.DataSource = dt

        DataGridViewX1.ColumnHeadersDefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight

        DataGridViewX1.DefaultCellStyle.Format = "N2"

        Me.DataGridViewX1.Columns("fecha").DefaultCellStyle.Format = "d"

        Dim i As Integer

        For i = 0 To DataGridViewX1.Columns.Count - 1

            DataGridViewX1.Columns.Item(i).SortMode = DataGridViewColumnSortMode.Programmatic

        Next i

    End Sub

    Private Sub fecha_consulta_ValueChanged(sender As Object, e As EventArgs) Handles fecha_consulta.ValueChanged

        fechac = Format(fecha_consulta.Value.Date, "yyyy-MM-dd")

    End Sub

    Private Sub Regresar_Click(sender As Object, e As EventArgs) Handles ButtonX1.Click

        desconectar()

        Me.Close()

    End Sub

End Class