Regular Expression Validator to Trap non-numeric entry.

ValidationExpression="^\d+$"

That did not work.
Any other suggestions?
Thanks,

To BuggyCoder:

<asp:TextBox ID="txtMinPrice" runat="server" Width="45px"
    onTextChanged = "txtMinPrice_TextChanged" CausesValidation="true">
    </asp:TextBox>

<asp:RegularExpressionValidator ID="valMinPrice" runat="server"
                            ErrorMessage="The Minimum Price needs to be numeric. "
                            ControlToValidate="txtMinPrice" SetFocusOnError="true"
                            EnableClientScript="False" Display="Dynamic"
                            ValidationExpression="^\d+$">
                        </asp:RegularExpressionValidator>

     protected void txtMinPrice_TextChanged(object sender, EventArgs e)

    {
        int Test1 = 0;
       if (this.IsValid)
        {
        Test1 = 1;
        }
    }

Error:

Page.IsValid cannot be called before validation has taken place.
It should be queried in the event handler for a control that has
CausesValidation=True and initiated the postback,
or after a call to Page.Validate.

you are applying it in text changed event of text box, this event will fire with every change in textbox data.
Ideally IsValid should be called on button click where we like to validate data before the final submit....

In your case you are making your text box to cause validation, this is not right or a good practice.
Suggest have a button and make its cause validation true and remove causevalidation from textbox....

To BasicInstinct

<asp:RangeValidator ID="valMinPrice" runat="server"
                        ErrorMessage="The Minimum Price needs to be numeric and between 1 and 100"
                        MaximumValue="100"
                        MinimumValue="1"
                        ControlToValidate="txtMinPrice" Display="Dynamic" SetFocusOnError="True">
                </asp:RangeValidator>

Error on any value entered except "1.00" or "1".

This is what I did that works.  It is complex, but does the job.

I used the TextChanged event. Then disabled the main process button if the entry was not numeric.

Based on
https://www.experts-exchange.com/questions/22806510/IsNumeric.html

<asp:TextBox ID="txtMinPrice" runat="server" Width="45px"
    onTextChanged = "txtMinPrice_TextChanged" AutoPostBack="True">
    </asp:TextBox>

Code behind:

 public void txtMinPrice_TextChanged(object sender, EventArgs e)
    {
        lblResult.Text = "";
        string strEntered = txtMinPrice.Text;
        bool blnIsNumeric = IsNumeric(strEntered);
        if (!blnIsNumeric)
        {
            lblResult.Text = "Price must be numeric and between 1.00 and 100.00";
            cmdGetResults.Enabled = false;
         }

        else
        {
            cmdGetResults.Enabled =true;
        }
        return;
    }

     public static bool IsNumeric(string pstrEntry)
            {
                bool isNum;
                double retNum;

                isNum = Double.TryParse(Convert.ToString(pstrEntry),
                    System.Globalization.NumberStyles.Any,
                    System.Globalization.NumberFormatInfo.InvariantInfo, out retNum);

                return isNum;

            }

I appreciate the suggestions made and the effort spent.<br /><br />That's why I divided the points evenly.<br /><br />Thanks,