How to Create a Datatable In C#

Question

Step 1 :

Declare A Datatable

Ex
 DataTable Dt = new DataTable();

Step 2:

Create a Datatable Columns

Ex
            DataColumn RollNo= new DataColumn();
            DataColumn Name= new DataColumn();
            DataColumn Std= new DataColumn();
            DataColumn BDate= new DataColumn();

            RollNo.ColumnName = "RollNo";
            Name.ColumnName = "Name";
            Std.ColumnName = "Std";
            BDate.ColumnName = "BDate";

            Dt .Columns.Add(RollNo);
            Dt .Columns.Add(Name);
            Dt .Columns.Add(Std);
            Dt .Columns.Add(BDate);

Step 3:

Create A row And Fill It

Ex

  DataRow row;
  row = Dt.NewRow();
  row["RollNo"] ="1";
  row["Name"] = "Vicky";
  row["Std"] = "12Std";
  row["BDate"] ="17-11-1990";
  Dt.Rows.Add(row);


-----------------------------------------------------------------
Brijesh Kumar Prajapati
Jr.Software Devloper,
Softyoug Solution Pvt Ltd
Vapi,
Gujarat,
India

Answer 1

You'll need to convert to strings to avoid this problem:

(DateTime.TryParse(maskedTextBox1.Text, out dtparsedDate) ? dtparsedDate.ToString() : "null") 

Notice that it's never necessary to explicitly test whether a bool expression is true.

Notice also that it's not necessary to convert dtParsedDate to a DateTime, as it's a DateTime already. 

Answer 2

Hi Vulpes, Santhosh,

thanks allot for your fast replies.

If i don't convert null to datetime, it is giving me error.

because:
you can check this one: if i write like this it is giving me error of "can not implicit conversion between system.datetime and null"

(DateTime.TryParse(maskedTextBox1.Text, out dtparsedDate) == true ? Convert.ToDateTime(dtparsedDate) : null) 
 

Darma

Answer 3

darma,

If you use Convert.ToDateTime(null) when building your SQL command, then you'll end with a string containing this:

"01/01/0001 00:00:00"

which may be an invalid value for the corresponding column in the database.

Santhosh's point is that you should use "null" instead which should then be translated to NULL in the database assuming (Hemant's point) that the column allows nulls.

Answer 4

Then check whether the columns tyou are tring to insert allow null values. also check whether any integer columns.IIf there are integer columns, then check and do conversion before insert

Answer 5

Hi Santhosh,

If user does not enters the date,  it is working well. 

Only my problem with textboxes only.

Darma

Answer 6

Why you are converting null to datetime..Just save it as null. No conversion needed

Answer 7

Hi,

Here is my code:

DateTime dtparsedDate = new DateTime();

                string insertsql = "insert into Table1 (ProjectId, ID, PID, Nr, note, Out, Target, Delivery, name,  Out1, Target1, Delivery1, Notes) " +

                                          "values ('" + CmbProjectid.Text + "', '" + ID.SelectedItem + "', '" + textBox1.Text + "', '" + textBox2.Text +

                                          "', '" + textBox3.Text + "', '" + (DateTime.TryParse(maskedTextBox1.Text, out dtparsedDate) == true ? Convert.ToDateTime(dtparsedDate) : Convert.ToDateTime(DBNull.Value)) + "', '" + (DateTime.TryParse(maskedTextBox2.Text, out dtparsedDate) == true ? Convert.ToDateTime(dtparsedDate) : Convert.ToDateTime(null)) + "', '" + (DateTime.TryParse(maskedTextBox3.Text, out dtparsedDate) == true ? Convert.ToDateTime(dtparsedDate) : Convert.ToDateTime(null)) +

                                          "', '" + textBox4.Text + "', '" + (DateTime.TryParse(maskedTextBox4.Text, out dtparsedDate) == true ? Convert.ToDateTime(dtparsedDate) : Convert.ToDateTime(null)) + "', '" + (DateTime.TryParse(maskedTextBox5.Text, out dtparsedDate) == true ? Convert.ToDateTime(dtparsedDate) : Convert.ToDateTime(null)) + "', '" + (DateTime.TryParse(maskedTextBox6.Text, out dtparsedDate) == true ? Convert.ToDateTime(dtparsedDate) : Convert.ToDateTime(null)) + "', '" + textBox4.Text + "');";

                SqlCommand insertcmd = new SqlCommand(insertsql, con1);

                insertcmd.ExecuteNonQuery();

                MessageBox.Show("Data Added Successfully", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);


Is user does not enter data in one textbox, than it is giving error.

Whatever user does not enter the data, that should save in the table1 as nulls.


Darma

Answer 8

Show us ur c# code

Answer 9

You have to alter the table column property as Allow Null =True.Then you can insert the null values also.