Сохраните пустые данные в базе данных, используя форму дизайна материала, используя c #

Question

Я использовал форму дизайна материала в формате html и установил EnableEventValidation=false после нажатия кнопки save, чтобы сохранить данные на сервере SQL, однако на сервере SQL сохранены пустые данные

<div class="form">
    <h1>Patient Information</h1>

    <div class="form-group">
        <input type="text" runat="server" id="Fname" required="required" />
        <label for="input" class="control-label">First Name</label><i class="bar"></i>
    </div>
    <div class="form-group">
        <input type="text" runat="server" id="Lname" required="required" />
        <label for="input" class="control-label">Last Name</label><i class="bar"></i>
    </div>
    <div class="form-group">
        <input type="text" runat="server" id="Address" required="required" />
        <label for="input" class="control-label">Address</label><i class="bar"></i>
    </div>
    <div class="form-group">
        <input type="text" runat="server" id="city" required="required" />
        <label for="input" class="control-label">City</label><i class="bar"></i>
    </div>

    <div class="form-group">
        <select runat="server" id="gender">
            <option>Male</option>
            <option>Female</option>
        </select>
        <label for="select" class="control-label">Gender</label><i class="bar"></i>
    </div>
    <div class="form-group">
        <label class="label-input100" for="date">Date Of Birth</label>
        <input type="date" id="birth" runat="server" name="datePurchase" />
    </div>
    <div class="form-group">
        <input type="text" runat="server" id="ssec" required="required" />
        <label for="input" class="control-label">Social Security</label><i class="bar"></i>
    </div>
    <div class="form-group">
        <select runat="server" id="inppSel">
        </select>
        <input runat="server" type="hidden" style="color: red;" id="inpTxt" />
        <label for="select" class="control-label">Patient Case</label><i class="bar"></i>
    </div>
    <div class="button-container">
        <button onserverclick="save" type="submit" class="button" id="addnew" runat="server"><span>Submit</span></button>
    </div>
</div>

C #:

DataBaseConnection db = new DataBaseConnection();
db.disconnect();

string sql1 = "INSERT INTO TBL_Persons VALUES( @First_Name, @Last_Name, @Address, @City)";

SqlCommand cmd1 = new SqlCommand(sql1, db.connect());
cmd1.Parameters.AddWithValue("@First_Name", Fname.Value);
cmd1.Parameters.AddWithValue("@Last_Name", Lname.Value);
cmd1.Parameters.AddWithValue("@Address", Address.Value);
cmd1.Parameters.AddWithValue("@City", city.Value);

cmd1.ExecuteNonQuery();

string sql2 = "INSERT INTO TBL_Patients VALUES(@Gender, @Date_OF_Birth, @Social_Security, @Person_ID, @Case_ID)";
db.disconnect();

string sql3 = "SELECT MAX(Person_ID) FROM TBL_Persons ";

SqlCommand cmd2 = new SqlCommand(sql3, db.connect());
int max = (int)(cmd2.ExecuteScalar());
db.disconnect();

SqlCommand cmd3 = new SqlCommand(sql2, db.connect());
cmd3.Parameters.AddWithValue("@Gender", gender.Items[gender.SelectedIndex].Text);
cmd3.Parameters.AddWithValue("@Date_OF_Birth", birth.Value);
cmd3.Parameters.AddWithValue("@Social_Security", ssec.Value);
cmd3.Parameters.AddWithValue("@Person_ID", max);
cmd3.Parameters.AddWithValue("@Case_ID", inpTxt.Value);

cmd3.ExecuteNonQuery();