On Page1.aspx I have 3 txtBoxes with Compare Validators that ensure they are of type Currency.

On Page2.aspx I have another text box called txtResult whose job it is to display the sum of the other 3 txtBoxes when btnCalculate is clicked on Page1.

Problem: I can't get the 3 txtBoxes to be treated as doubles and not strings. If txtBox values are 1, 3, and 8, txtResult will be 138 and not 12.

I tried try parsing but ~~it wasn't allowed~~ failed to compile.

Code behind Page1:

```
protected void btnCalculate_Click(object sender, EventArgs e)
{
    if (IsValid)
    {
        Server.Transfer("Page2.aspx");
    }
}

```

Code behind Page2:

```
if (!IsPostBack)
{
    Page lastPage = (Page)Context.Handler;
    txtResult.Text = ((TextBox)lastPage.FindControl("txtGross")).Text
        + ((TextBox)lastPage.FindControl("txtValueOfAssets")).Text
        + ((TextBox)lastPage.FindControl("txtInvestments")).Text;
}

```

Attempt to use `TryParse`:

```
txtResult.Text = 
    double.TryParse(((TextBox)lastPage.FindControl("txtGross")).‌​Text, out gross);

```

Errors with:

> 
> Cannot implicitly covert bool to string
> 
> 
>