How to insert Null value to Data Base using C# in ASP.Net

This is my form(C#) and I want to store this data in sql server 2008 table name called Table1, this is the first row/record  I am inserting in table1 table.

View of table after inserting the first row/record in table1

Table1

After that I want to store the second row/record in the table1

View of table after inserting the second row/record in table1

Table1

Hi appguruz16,

I have created a sample which fullfill your requirement

HTML

<div>
    <table>
        <tr>
            <td>
                <asp:Label Text="ID" runat="server" />
            </td>
            <td>
                <asp:TextBox ID="txtID" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label Text="NAME" runat="server" />
            </td>
            <td>
                <asp:TextBox ID="txtName" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label Text="DATA1" runat="server" />
            </td>
            <td>
                <asp:TextBox ID="txtData1" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label Text="DATA2" runat="server" />
            </td>
            <td>
                <asp:TextBox ID="txtData2" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label Text="DATA3" runat="server" />
            </td>
            <td>
                <asp:TextBox ID="txtData3" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label Text="DATA4" runat="server" />
            </td>
            <td>
                <asp:TextBox ID="txtData4" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Label Text="DATA5" runat="server" />
            </td>
            <td>
                <asp:TextBox ID="txtData5" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Button ID="btnSubmit" OnClick="Save" Text="Submit" runat="server" />
            </td>
        </tr>
    </table>
    <br />
    <asp:GridView ID="gvData" runat="server">
        <EmptyDataTemplate>
            <tr>
                <th scope="col">
                    ID
                </th>
                <th scope="col">
                    NAME
                </th>
                <th scope="col">
                    DATA1
                </th>
                <th scope="col">
                    DATA2
                </th>
                <th scope="col">
                    DATA3
                </th>
                <th scope="col">
                    DATA4
                </th>
                <th scope="col">
                    DATA5
                </th>
            </tr>
            <tr>
                <td colspan="7">
                    No Records Found!
                </td>
            </tr>
        </EmptyDataTemplate>
    </asp:GridView>
</div>

C# Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        BindGrid();
    }
}

protected void Save(object sender, EventArgs e)
{
    string constr = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
    SqlConnection con = new SqlConnection(constr);
    string query = "INSERT INTO Table1(ID,NAME,DATA1,DATA2,DATA3,DATA4,DATA5) VALUES(@Id,@Name,@Data1,@Data2,@Data3,@Data4,@Data5)";
    SqlCommand cmd = new SqlCommand(query);
    cmd.Connection = con;
    con.Open();
    cmd.Parameters.AddWithValue("@Id", txtID.Text.Trim());
    cmd.Parameters.AddWithValue("@Name", txtName.Text.Trim());
    if (!string.IsNullOrEmpty(txtData1.Text.Trim()))
    {
        cmd.Parameters.AddWithValue("@Data1", txtData1.Text.Trim());
    }
    else
    {
        cmd.Parameters.AddWithValue("@Data1", DBNull.Value);
    }
    if (!string.IsNullOrEmpty(txtData2.Text.Trim()))
    {
        cmd.Parameters.AddWithValue("@Data2", txtData2.Text.Trim());
    }
    else
    {
        cmd.Parameters.AddWithValue("@Data2", DBNull.Value);
    }
    if (!string.IsNullOrEmpty(txtData3.Text.Trim()))
    {
        cmd.Parameters.AddWithValue("@Data3", txtData3.Text.Trim());
    }
    else
    {
        cmd.Parameters.AddWithValue("@Data3", DBNull.Value);
    }
    if (!string.IsNullOrEmpty(txtData4.Text.Trim()))
    {
        cmd.Parameters.AddWithValue("@Data4", txtData4.Text.Trim());
    }
    else
    {
        cmd.Parameters.AddWithValue("@Data4", DBNull.Value);
    }
    if (!string.IsNullOrEmpty(txtData5.Text.Trim()))
    {
        cmd.Parameters.AddWithValue("@Data5", txtData5.Text.Trim());
    }
    else
    {
        cmd.Parameters.AddWithValue("@Data5", DBNull.Value);
    }
    cmd.ExecuteNonQuery();
    con.Close();
    // lblMessage.Visible = true;
    BindGrid();
}

public void BindGrid()
{
    string constr = ConfigurationManager.ConnectionStrings["ConString"].ConnectionString;
    SqlConnection con = new SqlConnection(constr);
    string query = "SELECT * FROM Table1";
    SqlCommand cmd = new SqlCommand(query);
    cmd.Connection = con;
    SqlDataAdapter sda = new SqlDataAdapter(cmd);
    DataTable dt = new DataTable();
    sda.Fill(dt);
    gvData.DataSource = dt;
    gvData.DataBind();
}

ScreenShot

Hope this works for you.