将数据类型nvarchar转换为int时出错

Question

我收到nvarchar转换为int的错误。我也试过解析，但它没有解决我的问题。那么我该如何解决这个问题呢？请给我解决方案。

存储过程中的代码：

ALTER PROCEDURE dbo.IDMaker
    (@Name varchar(50) = '',
     @Address varchar(50) = '',
     @Contact int,
     @EmergencyContact int,
     @BloodGroup varchar(50) = '',
     @Disease varchar(50) = '',
     @Drug varchar(50) = '',
     @Operation varchar(50),
     @ID int = 0)   
AS
BEGIN
    IF(@Operation = 1)
    BEGIN
        INSERT INTO IDRegis(Name, Address, Contact, EmergencyContact, BloodGroup, Disease, Drug) 
        VALUES (@Name, @Address, @Contact, @EmergencyContact, @BloodGroup, @Disease, @Drug)

        RETURN
    END

Windows窗体中的代码：

//int contact, emcontact;
//if (!Int32.TryParse(txtphone.Text, out contact))
//{
//    MessageBox.Show("Enter Valid number...");
//    return;
//}

//if (!Int32.TryParse(txtemphone.Text, out emcontact))
//{
//    MessageBox.Show("Enter Valid number...");
//    return;
//}

if (objmyclass.con.State != ConnectionState.Open)
{
    objmyclass.con.Open();
}

SqlCommand cmd = new SqlCommand("IDMaker", objmyclass.con);
cmd.CommandType = CommandType.StoredProcedure;

cmd.Parameters.AddWithValue("@Name", txtname.Text);
cmd.Parameters.AddWithValue("@Address", txtadd.Text);
cmd.Parameters.AddWithValue("@Contact", txtphone.Text);
cmd.Parameters.AddWithValue("@EmergencyContact",txtemphone.Text);
cmd.Parameters.AddWithValue("@BloodGroup", txtbg.Text);
cmd.Parameters.AddWithValue("@Disease", txted.Text);
cmd.Parameters.AddWithValue("@Drug", txtdrug.Text);
cmd.Parameters.AddWithValue("@Operation", 1);

int i = cmd.ExecuteNonQuery();    

if (i > 0)
{
    MessageBox.Show("Record Successfully Inserted....");
}