How to write the code for search criteria in asp.net????

Store PROCEDURE In Sql Side Create

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ALTER PROCEDURE [dbo].[DailyReportGrid_Criteria]
@Criteria varchar(max)

AS
declare @Condition as varchar(max)                       
SET @Condition =''

BEGIN
    SET @Condition ='
    With a as (
select Count(ClientMaster.ClientId) as ClientEntry,ClientMaster.DataEnterDate,
       COUNT(FolloupMaster.intclientfolloupid)as FollowEntry,DataEnterDate,FolloupMaster,
       Count(LeadMaster.intLeadId) as LeadEntry,LeadMaster.dtleadDate,
       COUNT(QuotationMasterNew.QuotationId) as QuotationEntry,QuotationMasterNew.SubmitDate,       
       COUNT(InvoiceMasterNew.InvoiceId) as InvoiceEntry,InvoiceMasterNew.InvoiceDate,
       COUNT(PaymentMaster.PaymentId) as PaymentEntry,PaymentMaster.PaymentDueDate
from
        ClientMaster,
        FolloupMaster,
        LeadMaster,
        QuotationMasterNew,
        InvoiceMasterNew,
        PaymentMaster
         )
        select EmployeeMaster.intEmployeeID,
        (EmployeeMaster.strFirstName + '' '' + isnull(EmployeeMaster.strMiddleName, '''') + '' '' + EmployeeMaster.strLastName) as FullName,
        a.ClientEntry,a.FollowEntry,a.LeadEntry,a.QuotationEntry,a.InvoiceEntry,a.PaymentEntry,
        ClientMaster.DataEnterDate,FolloupMaster.dtFollowDate,LeadMaster.dtleadDate,QuotationMasterNew.SubmitDate,InvoiceMasterNew.InvoiceDate,PaymentMaster.PaymentDueDate
        --a.DataEnterDate,a.dtFollowDate,a.dtleadDate,a.SubmitDate,a.InvoiceDate,a.PaymentDueDate
         from a,EmployeeMaster,ClientMaster,FolloupMaster,LeadMaster,QuotationMasterNew,InvoiceMasterNew,PaymentMaster ' + '' + @Criteria + ''
   
   
    print @Condition
   
    exec(@Condition)
   
    END

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Cs Code In Button Click Event To Write Code .............................

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string  SearchCriteria = " WHERE 1=1 ";

        if (Session["Role"].Equals("Admin"))
        {
            if (ddlEmployee.SelectedIndex != 0 && ddlEmployee.SelectedIndex != -1)
            {
                SearchCriteria = SearchCriteria + " AND EmployeeMaster.intEmployeeId=" + Convert.ToInt16(ddlEmployee.SelectedValue) + "";
            }
        }
        else if (Session["Role"].Equals("Operator"))
        {
            SearchCriteria = SearchCriteria + " AND EmployeeMaster.intEmployeeId=" + Convert.ToInt16(ddlEmployee.SelectedValue) + "";
        }


        //if (ddlEmployee.SelectedIndex != 0)
        //{
        //    SearchCriteria = SearchCriteria + " AND EmployeeMaster.intEmployeeID=" + Convert.ToInt16(ddlEmployee.SelectedValue) + "";
        //}
        if (ddlCompanyName.SelectedIndex != 0)
        {
            SearchCriteria = SearchCriteria + " AND InvoiceMAsterNew.CompanyId=" + Convert.ToInt16(ddlCompanyName.SelectedValue) + "";
        }
        if (txtTodate.Text != "")
        {
            SearchCriteria = SearchCriteria + " AND InvoiceMAsterNew.InvoiceDate>='" + txtTodate.Text.ToString() + "'";
        }
        if (txtFromdate.Text != "")
        {
            SearchCriteria = SearchCriteria + " AND InvoiceMAsterNew.InvoiceDate<='" + txtFromdate.Text.ToString() + "'";
        }


        Session["criteria"] = SearchCriteria.ToString();
        Session["criteria"] = Session["criteria"].ToString().Replace("''", "'");
        Response.Redirect("InvoiceSummaryReportResult.aspx");

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