Field from the dataset how can I change my data type;

Question

0.00/5 (No votes)

See more:

I have a function that you return on my table
Field from the dataset how can I change my data type;
ds.Columns("dataletter").DataType = GetType(string);

C#

public DataTable letterrecive(string tblname, string Filedname, string Where, string Order)
        {
            if (Where.Trim() == "")
               Where = " 1=1 ";
            command.CommandText = "Select " + Filedname + " From " + tblname + " where " + Where + Order;
            SqlDataAdapter search1 = new SqlDataAdapter(command);
            DataTable dt = new DataTable();
            DataSet ds = new DataSet();
            search1.SelectCommand = command;
            command.Connection = connection;
            search1.Fill(ds, "dt");
            
             return ds.Tables[0];
        }

[edit]Added pre tags [/edit]

Posted 12-Apr-11 7:12am

saeed1364

Updated 12-Apr-11 7:45am

Albin Abel

v4

Add a Solution

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Albin Abel · Answer 1 · 2011-04-12T07:57:00

Solution 1

Add the column with the right type before data binding. At data binding event convert your data to the correct type and bind to that column. Error will be occurring if you change column data type after data bound.

Posted 12-Apr-11 7:57am

Albin Abel

Wendelius · Answer 2 · 2011-04-12T08:56:00

Since you don't add the columns into the data table before you do the fetch, the data type in your column in the data table will be the corresponding datatype from what's in the database.

Seems that you're trying to handle multiple different kind of queries with this method. What I actually would suggest is that instead of trying to build a 'common' fetch mechanism where you use concatenated strings, build the 'specialized' SqlCommand instances and use SqlParameters instead of literal conditions. If you like you can have a helper function to execute the commands and to fill a datatable.

If you, for some reason, need to have a string in some columns, you can also handle the conversion in the database using for example cast[^]