error converting datatype varchar to float

Thank u every body i got my answer

Hello Eben,you will face such type of SQLException When there be a datatype mismatch.
So cross check in sqlserver t able that the column having data type is decimal and you want to save a varchar value or vice-versa.

if you could share the more details like Table structure and SP then we could point out exactly

my tble is
  customernumber-float
   customer name-nvarchar(255)
    customerpinNumber-float
   my aspx.cs code is
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using System.Data;
using System.Data.SqlClient;
using System.Text;
namespace EbenMpbileApp
{
    public partial class Ebenmobile : System.Web.UI.Page
    {
        float dec2DivId;
        protected void Page_Load(object sender, EventArgs e)
        {

        }
        public override void VerifyRenderingInServerForm(Control control)
        {
            /* Verifies that the control is rendered */
        }
        protected void btndownload_Click(object sender, EventArgs e)
        {

            if (ddllist.SelectedIndex == 1)
            {
                if (TextBox1.Text != string.Empty)
                {                  
                    dec2DivId = float.Parse(TextBox1.Text);
                    EbenSp spmobile = new EbenSp();
                    DataTable dtblc = new DataTable();
                    dtblc =spmobile.pinNumberSearch(dec2DivId));
                    Response.Clear();
                    Response.Buffer = true;
                    Response.AddHeader("content-disposition", "attachment;filename=PinnumberSearch.csv");
                    Response.Charset = "";
                    Response.ContentType = "application/text";
                    StringBuilder sb = new StringBuilder();
                    for (int k = 0; k < dtblc.Columns.Count; k++)
                    {
                        sb.Append(dtblc.Columns[k].ColumnName + ',');
                    }
                    //append new line
                    sb.Append("\r\n");
                    for (int i = 0; i < dtblc.Rows.Count; i++)
                    {
                        for (int k = 0; k < dtblc.Columns.Count; k++)
                        {
                            sb.Append(dtblc.Rows[i][k].ToString().Replace(",", ";") + ',');
                        }
                        //append new line
                        sb.Append("\r\n");
                    }
                    Response.Output.Write(sb.ToString());
                    Response.Flush();
                    Response.End();
                }
            }         
        }
    }
}