Clear ASP.Net FileUpload and Image control after insert using C# and VB.Net

Hi RichardSa,

Check the file upload has file or not. If no file then set the byte as null. The after checking pass the parameter as DBNull if byte is null. 

Use below updated code.

HTML

<div class="table-cover" style="max-width: 90%; padding-left: 10%;">
    <div class="row">
        <div class="col">
            Enter Name:<br />
            <asp:TextBox ID="txtName" runat="server" />
        </div>
        <div class="col">
            Enter Subject:<br />
            <asp:TextBox ID="txtSubject" runat="server" />
        </div>
    </div>
    <br />
    <asp:TextBox ID="txtComment" runat="server" Font-Size="9pt" placeholder="Your Posts" TextMode="MultiLine" CssClass="form-control" />
    <asp:FileUpload ID="postimgupload" runat="server" Style="display: none" />
    <img id="imgFileUpload" alt="" runat="server" src="~/images/sidenav/camera.png" width="28" height="28" style="cursor: pointer;" />
    <br />
    <br />
    <asp:Button ID="Button1" runat="server" Text="Post" class="btn btn-primary navbar-btn" OnClick="Button1_Click1" />
</div>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script type="text/javascript">
    $(function () {
        var fileUpload = $("[id*=postimgupload]");
        var img = $("[id*=imgFileUpload]");
        img.click(function () { fileUpload.click(); });
        fileUpload.change(function () {
            var reader = new FileReader();
            reader.onload = function (e) {
                $("[id*=imgFileUpload]").attr("src", e.target.result);
            }
            reader.readAsDataURL($(this)[0].files[0]);
        });
    });
</script>

Namespaces

C#

using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.IO;

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient
Imports System.IO

Code

C#

SqlCommand cmd = new SqlCommand();
SqlDataAdapter sda = new SqlDataAdapter();
DataSet ds = new DataSet();
DataTable dt = new DataTable();
private SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString);
protected void Button1_Click1(object sender, EventArgs e)
{
    if (!string.IsNullOrEmpty(txtName.Text) & !string.IsNullOrEmpty(txtComment.Text) & !string.IsNullOrEmpty(txtSubject.Text))
    {
        byte[] image = null;
        if (postimgupload.HasFile)
        {
            Stream s = postimgupload.PostedFile.InputStream;
            BinaryReader br = new BinaryReader(s);
            image = br.ReadBytes((Int32)s.Length);
        }

        con.Open();
        SqlCommand cmd = new SqlCommand("insert into [Table] (Username,Subject,Comment,PostedDate,imgpost) values(@Username,@Subject,@Comment,@PostedDate,@imgpost)", con);
        cmd.Parameters.AddWithValue("@Username", txtName.Text);
        cmd.Parameters.AddWithValue("@Subject", txtSubject.Text);
        cmd.Parameters.AddWithValue("@Comment", txtComment.Text);
        cmd.Parameters.AddWithValue("@PostedDate", DateTime.Now);
        if (image == null || image.Length == 0)
        {
            cmd.Parameters.Add("@imgpost", SqlDbType.VarBinary, -1).Value = DBNull.Value;
        }
        else
        {
            cmd.Parameters.AddWithValue("@imgpost", image);
        }
        cmd.ExecuteNonQuery();
        con.Close();
        Response.Redirect(Request.Url.AbsoluteUri);
    }
    else
    {

    }
}

VB.Net

Private cmd As SqlCommand = New SqlCommand()
Private sda As SqlDataAdapter = New SqlDataAdapter()
Private ds As DataSet = New DataSet()
Private dt As DataTable = New DataTable()
Private con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)

Protected Sub Button1_Click1(ByVal sender As Object, ByVal e As EventArgs)
    If Not String.IsNullOrEmpty(txtName.Text) And Not String.IsNullOrEmpty(txtComment.Text) And Not String.IsNullOrEmpty(txtSubject.Text) Then
        Dim image As Byte() = Nothing
        If postimgupload.HasFile Then
            Dim s As Stream = postimgupload.PostedFile.InputStream
            Dim br As BinaryReader = New BinaryReader(s)
            image = br.ReadBytes(CType(s.Length, Int32))
        End If
        con.Open()
        Dim cmd As SqlCommand = New SqlCommand("insert into [Table] (Username,Subject,Comment,PostedDate,imgpost) values(@Username,@Subject,@Comment,@PostedDate,@imgpost)", con)
        cmd.Parameters.AddWithValue("@Username", txtName.Text)
        cmd.Parameters.AddWithValue("@Subject", txtSubject.Text)
        cmd.Parameters.AddWithValue("@Comment", txtComment.Text)
        cmd.Parameters.AddWithValue("@PostedDate", DateTime.Now)
        If image Is Nothing OrElse image.Length = 0 Then
            cmd.Parameters.Add("@imgpost", SqlDbType.VarBinary, -1).Value = DBNull.Value
        Else
            cmd.Parameters.AddWithValue("@imgpost", image)
        End If
        cmd.ExecuteNonQuery()
        con.Close()
        Response.Redirect(Request.Url.AbsoluteUri)
    Else
    End If
End Sub