I got the solution somehow:-
var queryuserinfo = (from userinfo in dbContext.User_Informations
join reg in dbContext.registers on userinfo.UserName equals reg.UserName
join regdet in dbContext.registerdetails on reg.UserName equals regdet.UserName
where userinfo.UserName == Session["MatriUser"].ToString()
select new
{
reg.height, reg.region, reg.employed, userinfo.Location, reg.profession, reg.about,
reg.bodytype, reg.cases,reg.complexion, reg.diet, reg.drink, reg.smoke,
reg.education, reg.employment, reg.income,
}).FirstOrDefault();
if(queryuserinfo!=null)
{
Height.Text = queryuserinfo.height;
Religion.Text = queryuserinfo.region.Remove(1).ToUpper()+queryuserinfo.region.Substring(1);
Working.Text = queryuserinfo.employed.Remove(1).ToUpper() + queryuserinfo.employed.Substring(1);
Living_In.Text = queryuserinfo.Location.Remove(1).ToUpper() + queryuserinfo.Location.Substring(1);
Profession.Text = queryuserinfo.profession.Remove(1).ToUpper() + queryuserinfo.profession.Substring(1);
BodyType.Text = queryuserinfo.bodytype.Remove(1).ToUpper() + queryuserinfo.bodytype.Substring(1);
SpecialCase.Text = queryuserinfo.cases.Remove(1).ToUpper() + queryuserinfo.cases.Substring(1);
Complexion.Text = queryuserinfo.complexion.Remove(1).ToUpper() + queryuserinfo.complexion.Substring(1);
Diet.Text = queryuserinfo.diet.Remove(1).ToUpper() + queryuserinfo.diet.Substring(1);
Drink.Text = queryuserinfo.drink.Remove(1).ToUpper() + queryuserinfo.drink.Substring(1);
Smoke.Text = queryuserinfo.smoke.Remove(1).ToUpper() + queryuserinfo.smoke.Substring(1);
HighestQualification.Text = queryuserinfo.education.Remove(1).ToUpper() + queryuserinfo.education.Substring(1);
Employed.Text = queryuserinfo.employment.Remove(1).ToUpper() + queryuserinfo.employment.Substring(1);
EmployedIn.Text = queryuserinfo.employed.Remove(1).ToUpper() + queryuserinfo.employed.Substring(1);
AnnualIncome.Text = queryuserinfo.income.Remove(1).ToUpper() + queryuserinfo.income.Substring(1);
about.Text = queryuserinfo.about.Remove(1).ToUpper() + queryuserinfo.about.Substring(1);
}
else
{
ClientScript.RegisterStartupScript(this.GetType(),"","<script>alert('Can't Retrieve Some Details. Please Try Again.')</script>");
}