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Adding numeric data from a ds? Am I making this to hard?

Posted on 2004-09-28
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Last Modified: 2010-04-15

I have a ds with a couple of tables.  Each one is bound to a combo box where the user will select an option.  I need to keep the running total as they work through the form.

I have this:
Tot = System.Convert.ToString(dsBuilder.Tables["InputGear"].Rows[this.mmComboBox4.SelectedIndex]["se_price"].ToString());

Why is pulling data from the ds always in a string, that I have to convert to decimal, and then back to a string for show in a textbox?

I have to add a total of 8 selections.  Is there an easier way to do the math ?

TIA  
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Question by:srussell705
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9 Comments
 
LVL 10

Expert Comment

by:eternal_21
ID: 12172139
Why don't you try this?

Tot = String.Format("{0:#.##}", dsBuilder.Tables["InputGear"].Rows[this.mmComboBox4.SelectedIndex]["se_price"]);
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LVL 96

Expert Comment

by:Bob Learned
ID: 12173495
Pulling data from the datatable is not always a string.  It should be the type for the field.  You need to make sure that 'se_price' is a numeric value.

Bob
0
 
LVL 1

Expert Comment

by:ryeandi
ID: 12173943
hi srussell,

when you define the columns of the datatable you can set the data type for the integer column as such:

dsBuilder.Tables["InputGear"].Columns["se_price"].DataType = System.Type.GetType("System.Int16");

hope this helps,

rye
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Author Comment

by:srussell705
ID: 12173962

I hear what your saying.  It is typed to numeric against the real data.  This gets to my inital ? then.  

How do you pull it out of the object :
dsBuilder.Tables["InputGear"].Rows[this.mmComboBox4.SelectedIndex]["se_price"]

so you can add it into a allot of other calls like the above.  This is my actual code in 1 aspect of the switch

nTot = System.Convert.ToDecimal(dsBuilder.Tables["InputGear"].Rows[this.mmComboBox4.SelectedIndex]["se_price"].ToString());

nTot += System.Convert.ToDecimal(dsBuilder.Tables["GearRatio"].Rows[this.mmComboBox3.SelectedIndex]["se_price"].ToString());

nTot += System.Convert.ToDecimal(dsBuilder.Tables["Mounts"].Rows[this.mmComboBox2.SelectedIndex]["se_price"].ToString());

nTot += System.Convert.ToDecimal(dsBuilder.Tables["Lube"].Rows[this.mmComboBox5.SelectedIndex]["se_price"].ToString());

nTot += System.Convert.ToDecimal(dsBuilder.Tables["ShifterType"].Rows[this.mmComboBox6.SelectedIndex]["se_price"].ToString());

nTot += System.Convert.ToDecimal(dsBuilder.Tables["AssemblyArrange"].Rows[this.mmComboBox7.SelectedIndex]["se_price"].ToString());

nTot += System.Convert.ToDecimal(dsBuilder.Tables["OutputType"].Rows[this.mmComboBox8.SelectedIndex]["se_price"].ToString());
                              

I then take that value for presentation to the user:
this.mmTextBox99.Text=System.Convert.ToString(nTot);
this.mmTextBox99.Visible=true;

I think that I'm missing the obvious here in dealing with numerics in a ds.  

Thanks for the reply.
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LVL 96

Accepted Solution

by:
Bob Learned earned 50 total points
ID: 12173979
Stop converting ToString, and then back to decimal:

nTot = dsBuilder.Tables["InputGear"].Rows[this.mmComboBox4.SelectedIndex]["se_price"];

Bob
0
 
LVL 1

Author Comment

by:srussell705
ID: 12174011
Smacking fore head!

Thanks.

0
 
LVL 96

Expert Comment

by:Bob Learned
ID: 12174026
You're welcome.   Just remember not to smack too hard, you might leave a dent, and then people will notice *GRIN*

Bob
0
 
LVL 1

Expert Comment

by:ryeandi
ID: 12174413
you can refer the the data directly from the DataTable without converting:

Decimal nTot = dsBuilder.Tables["InputGear"].Rows[this.mmComboBox4.SelectedIndex]["se_price"];

just data type your column as such:

dsBuilder.Tables["InputGear"].Columns["se_price"].DataType = System.Type.GetType("System.Decimal");
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LVL 96

Expert Comment

by:Bob Learned
ID: 12180583
Is there an echo in here?


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