>Still battling with the ASP.NET GridView control.
>
>The problem this time is IFormatProvider and my lack of understanding of it.
>
>Say I have a simple 2-column grid I want to bind to a DataTable at runtime. The data comes from another table where I have to extract info depending on some conditions.
>
>Simplified:
>

>string sDescrip="";
>string sValue="";
>DataTable dt = new DataTable();
>DataRow dr;
>
>// add two columns
>dt.Columns.Add(new DataColumn("Description", typeof(String)));
>dt.Columns.Add(new DataColumn("Value", typeof(double)));
>// I have a foreach() loop here to work through another DataTable
>// and decide if want want to extract info from it for the grid (complex reasons)
>// say the condition is: iWantItCondition (for each item)
>if (iWantItCondition==true)
>{
>// oRow[oColumn.Columname] is the current row in the current column in the source table
>
>  // we move here to a column to get decription -- [code snipped]
>  sDescrip=oRow[oColumn.ColumnName].ToString();
>
>  // we move here to another column to get value -- [code snipped]
>  sValue=oRow[oColumn.ColumnName].ToString();
>  dr = dt.NewRow();
>  dr[0] = sDescrip;
>
>  // here's the problem
>  // I want to format the string depending on what it is (sometimes a percentage, sometimes currency)
>  // for example's simplicity let's deal only with Currency here
>
>  // this line doesn't work:
>  // Runtime error: "Input string was not in a correct format.
>  //    Couldn't store <$134.00> in Value Column. Expected type is Double."
>  dr[1] = double.Parse(sValue).ToString("C")
>
>  ////// debug:  this line works and it shows onscreen as $134.00 correctly
>  Response.Write(sValue + ": " + double.Parse(sValue).ToString("C") + "<br>");
>  ////// debug
>
>  dt.Rows.Add(dr);
>}
>
>// after done building the datarows, bind them to a grid
>this.GridViewOthers.DataSource = dt;
>this.GridViewOthers.DataBind();
>

>Why does the Response.Write work fine with proper Currency formatting, but the assignment to data row 2nd column dr[1] does not? dr[1] is defined as a double. The formatted value I want to store is parsed as a double.
>
>Do I have to save everything as a string to get formatting? The help samples for IFormatProvider are as clear as mud.
>
>Any ideas appreciated.

I'm pretty new at C# and ADO.NET so take the following with appropriate salt <g>

// Your line below explicitly says that the Value column stores Doubles:
dt.Columns.Add(new DataColumn("Value", typeof(double)));

// You give no idea what sValue is. I suspect that the result type of the following is not double:
dr[1] = double.Parse(sValue).ToString("C");
// so I'm guessing the compiler complaint is bang-on.
// Note in your original code you left off the trailing semi-colon - I assume that's a typo here
// and not in your actual code

// I also suspect the Response.Write call is working because it's either treating it as a string
// concatenation, or maybe Response.Write has enough overloads to successfully write "any old junk"
// to the screen (sorta like, IIRC, the VB6 MessageBox).

// I've run into a couple of similar cases where I couldn't figure out why what I thought was
// an explicit type conversion wouldn't work. In those cases I resorted to System.Convert.
// Assuming svalue can be meaningfully converted to a double, you could try
dr[1] = Convert.ToDouble( sValue );