List<SqlParameter> paras = new List<SqlParameter>();

        string wherSql = PreWhereSQL + GetQuerySql(paras);

string GetQuerySql(List<SqlParameter> paras)

    {

        StringBuilder where = new StringBuilder(" and 1=1");

        if (!string.IsNullOrEmpty(tbWorkOrderNo.Text.Trim()))

        {

            where.Append(" and SgWorkOrderNo like @p_SgWorkOrderNo");

            paras.Add(new SqlParameter("@p_SgWorkOrderNo", "%" + tbWorkOrderNo.Text.Trim() + "%"));

        }

        if (!string.IsNullOrEmpty(tbTitle.Text.Trim()))

        {

            where.Append(" and Title like @p_tbTitle");

            paras.Add(new SqlParameter("@p_tbTitle", "%" + tbTitle.Text.Trim() + "%"));

        }

        if (!string.IsNullOrEmpty(ddlCity.SelectedValue))

        {

            where.Append(" and CityName = @p_CityName");

            paras.Add(new SqlParameter("@p_CityName", ddlCity.SelectedValue));

        }

        if (!string.IsNullOrEmpty(ddlBussinessAttr.SelectedValue))

        {

            where.Append(" and ProductID = @p_ProductID");

            paras.Add(new SqlParameter("@p_ProductID", ddlBussinessAttr.SelectedValue));

        }

        if (!string.IsNullOrEmpty(tbStartTimeS.Text.Trim()))

        {

            where.Append(" and JieSuanStartTime >= @p_JieSuanStartTimeS");

            paras.Add(new SqlParameter("@p_JieSuanStartTimeS", tbStartTimeS.Text.Trim()));

        }

        if (!string.IsNullOrEmpty(tbStartTimeE.Text.Trim()))

        {

            where.Append(" and JieSuanStartTime <= @p_JieSuanStartTimeE");

            paras.Add(new SqlParameter("@p_JieSuanStartTimeE", tbStartTimeE.Text.Trim()));

        }

        if (!string.IsNullOrEmpty(ddlCheckStatus.SelectedValue))

        {

            where.Append(" and JieSuanStatus = @p_JieSuanStatus");

            paras.Add(new SqlParameter("@p_JieSuanStatus", ddlCheckStatus.SelectedValue));

        }

        return where.ToString();

    }

这个是有前置查询条件的，所有where的初始值为 and =