i want to select float value from database and show the result in textbox (asp.net)?

Question

I want to fetch float data (if exist) from database and after addition show the result in text box (TXT_grandtotal)

In my code its shows only numeric value

double price= 0;   
DataTable dt = new DataTable();

cmd.CommandText = "select total from productADD where auto_no='"+txt_autoNo.Text.Trim() + "'";
cmd.Connection = con;

SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);

foreach (DataRow row in dt.Rows)
{
    float id = (Convert.ToInt32(row["total"]));
    price = id + price;
    TXT_grandtotal.Text = (Convert.ToString(price));
}

Is total in float type? because this line `float id = (Convert.ToInt32(row["total"]));` is confusing — Saif, Aug 29 '19 at 06:30
You use `Convert.ToInt32` instead of `Convert.ToSingle()`. And btw: please don't insert user input directly into your query, use **paramterized queries** instead. Your code is open to [SQL injection](https://www.bobby-tables.com) — René Vogt, Aug 29 '19 at 06:31
I would strongly suggest reading the duplicate link on SQL Injection. Then, read up on Dapper. — mjwills, Aug 29 '19 at 06:52
lbl_nuToword.Text = NumberToWords(Convert.ToInt32(TXT_grandtotal.Text)); when i want to show the result in word its says the string is not in correct format ? — Travelers, Aug 29 '19 at 06:56
That is a new question. `NumberToWords` is not in your question. Please write a new question. — mjwills, Aug 29 '19 at 06:58

Saif · Answer 1 · 2019-08-29T06:57:39.210

First issue in your code is that you are not using parametrize query, secondly conversion was not correct, please check the following code if it help you

double price= 0;   
DataTable dt = new DataTable();

string sql = "select total from productADD where auto_no = @auto_no";

using (SqlConnection connection = new SqlConnection(/* connection info */))
{
        SqlCommand command = new SqlCommand(commandText, connection);
        command.Parameters.Add("@auto_no", SqlDbType.Int);
        command.Parameters["@auto_no"].Value = Int32.Parse(txt_autoNo.Text.Trim());
}

SqlDataAdapter da = new SqlDataAdapter(cmd);
da.Fill(dt);

foreach (DataRow row in dt.Rows)
{
    float id = (Convert.ToSingle(row["total"]));
    float price = id + price;
    TXT_grandtotal.Text = Convert.ToString(price)
}

score -2 · Accepted Answer · answered Aug 29 '19 at 06:38

-2

           cmd.CommandText = "SELECT SUM(CAST(total AS int)) AS total from productADD where auto_no='"+txt_autoNo.Text.Trim() + "'";

            cmd.Connection = con;

            SqlDataAdapter da = new SqlDataAdapter(cmd);

            da.Fill(dt);

            TXT_grandtotal.Text=Convert.ToString(dt.Rows[0]["total"]);

Note:-- You can Follow this method...here i'm Calculating the total Value...instead of using for Loop...

This will improve your performance..

you can use cast if your table data type as varchar

answered Aug 29 '19 at 06:38

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i will try this one also – Travelers Aug 29 '19 at 06:48
1

Please read https://stackoverflow.com/questions/14376473/what-are-good-ways-to-prevent-sql-injection - for other readers **do not use this answer**. – mjwills Aug 29 '19 at 06:53

i want to select float value from database and show the result in textbox (asp.net)?

2 Answers2