Pass TextBox values to variable in ASP.Net using C# and VB.Net

Hi ramco1917,

Please refer below sample.

HTML

Email:
<asp:TextBox ID="txtEmail" runat="server"></asp:TextBox><br />
Password:
<asp:TextBox ID="txtPassword" runat="server"></asp:TextBox><br />
<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="btnSubmit_Click" />
<hr />
<asp:Label ID="lblJson" runat="server" />

Code

C#

protected void btnSubmit_Click(object sender, EventArgs e)
{
    string body = "{" + string.Format(@"{2}""email"": ""{0}"",{2}""password"": ""{1}""{2}", txtEmail.Text, txtPassword.Text, Environment.NewLine) + "}";
    lblJson.Text = body;
}

VB.Net

Protected Sub btnSubmit_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim body As String = "{" & String.Format("{2}""email"": ""{0}"",{2}""password"": ""{1}""{2}", txtEmail.Text, txtPassword.Text, Environment.NewLine) & "}"
    lblJson.Text = body
End Sub

Screenshot