vb.net - I need help putting all the logic statements in the correct order -
when click search button, happen:
if search field empty, display message saying "please enter student number". if search field isn't empty, search database specific record matching user typed search field making sure there numbers in search field, if letter found, display message "numbers only", search db specific record. if record isn't found, display message saying "student not exist". if record found, populate fields data , based off of in record, enable buttons , change color.
that's want. , work...mostly. out of order or in wrong spot or something. can't figure out. catch statement towards bottom commented out because use work doesn't - again, or things out of order. i'm not advanced developer @ all, go easy on me.
here code click event of search button:
if stunumtxtbox.text = "" msgbox("please enter student number.", msgboxstyle.exclamation) stunumtxtbox.select() else try using connection new sqlconnection("data source=server-name\iawdb;initial catalog=iawdb;persist security info=true;integrated security=true") connection.open() dim dt new datatable dim ds new dataset dim da new sqldataadapter ds.tables.add(dt) da = new sqldataadapter("select distinct * student_info studentid = '" & stunumtxtbox.text & "'", connection) dim count = da.fill(dt) if count = 0 msgbox("student id not found.", msgboxstyle.critical) else dim g1 list(of string) = (from r datarow in dt r.field(of string)("g1") = "y" or r.field(of string)("g1") = "n" select r.field(of string)("g1")).tolist() me.g1button.backcolor = if(g1.contains("y"), color.green, if(g1.contains("n"), color.red, systemcolors.controldarkdark)) me.g1button.enabled = (g1.count > 0) dim g2 list(of string) = (from r datarow in dt r.field(of string)("g2") = "y" or r.field(of string)("g2") = "n" select r.field(of string)("g2")).tolist() me.g2button.backcolor = if(g2.contains("y"), color.green, if(g2.contains("n"), color.red, systemcolors.controldarkdark)) me.g2button.enabled = (g2.count > 0) dim af1 list(of string) = (from r datarow in dt r.field(of string)("af1") = "y" or r.field(of string)("af1") = "n" select r.field(of string)("af1")).tolist() me.af1button.backcolor = if(af1.contains("y"), color.green, if(af1.contains("n"), color.red, systemcolors.controldarkdark)) me.af1button.enabled = (af1.count > 0) dim af2 list(of string) = (from r datarow in dt r.field(of string)("af2") = "y" or r.field(of string)("af2") = "n" select r.field(of string)("af2")).tolist() me.af2button.backcolor = if(af2.contains("y"), color.green, if(af2.contains("n"), color.red, systemcolors.controldarkdark)) me.af2button.enabled = (af2.count > 0) dim af3 list(of string) = (from r datarow in dt r.field(of string)("af3") = "y" or r.field(of string)("af3") = "n" select r.field(of string)("af3")).tolist() me.af3button.backcolor = if(af3.contains("y"), color.green, if(af3.contains("n"), color.red, systemcolors.controldarkdark)) me.af3button.enabled = (af3.count > 0) dim pp1 list(of string) = (from r datarow in dt r.field(of string)("pp1") = "y" or r.field(of string)("pp1") = "n" select r.field(of string)("pp1")).tolist() me.pp1button.backcolor = if(pp1.contains("y"), color.green, if(pp1.contains("n"), color.red, systemcolors.controldarkdark)) me.pp1button.enabled = (pp1.count > 0) dim pp2 list(of string) = (from r datarow in dt r.field(of string)("pp2") = "y" or r.field(of string)("pp2") = "n" select r.field(of string)("pp2")).tolist() me.pp2button.backcolor = if(pp2.contains("y"), color.green, if(pp2.contains("n"), color.red, systemcolors.controldarkdark)) me.pp2button.enabled = (pp2.count > 0) dim pp3 list(of string) = (from r datarow in dt r.field(of string)("pp3") = "y" or r.field(of string)("pp3") = "n" select r.field(of string)("pp3")).tolist() me.pp3button.backcolor = if(pp3.contains("y"), color.green, if(pp3.contains("n"), color.red, systemcolors.controldarkdark)) me.pp3button.enabled = (pp3.count > 0) editstudenttoolstripmenuitem.enabled = true end if each datarow in dt.rows if stunumtxtbox.text = dt.rows(0)("studentid").tostring fnametxtbox.text = dt.rows(0)("firstname").tostring mnametxtbox.text = dt.rows(0)("midleinitial").tostring lnametxtbox.text = dt.rows(0)("lastname").tostring addresstxtbox.text = dt.rows(0)("addressstreet").tostring address2txtbox.text = dt.rows(0)("addressoption").tostring citytxtbox.text = dt.rows(0)("addresscity").tostring statetxtbox.text = dt.rows(0)("addressstate").tostring ziptxtbox.text = dt.rows(0)("addresszip").tostring countrytxtbox.text = dt.rows(0)("addresscountry").tostring celltxtbox.text = dt.rows(0)("contactcellphone").tostring studentidtxtbox.text = dt.rows(0)("studentid").tostring timeowedtxtbox.text = dt.rows(0)("timeowed").tostring studentnametextbox.text = lnametxtbox.text & "," & " " & fnametxtbox.text & " " & mnametxtbox.text else end if next end using catch se sqlexception 'if se.errorcode = -2146232060 'msgbox("enter numbers only.", msgboxstyle.information) msgbox(se.message) 'else msgbox(se.message) 'end if end try end if is there out there may tadddddddd bit better @ me, flip around me , make work , me understand changes made , why made? haha know, asking lot. i'm close though...i think.
well, first thing need test if stunumtxtbox.text contains value can parsed integer. easy way use integer.tryparse method. use right after test empty string. also, test empty string can better. use string.isnullorwhitespace method. see code example:
if not string.isnullorwhitespace(stunumtxtbox.text) dim integer if integer.tryparse(stunumtxtbox.text, i) '' string contains valid integer, can continue code here. else msgbox("enter numbers only.", msgboxstyle.information) stunumtxtbox.select() end if else msgbox("please enter student number.", msgboxstyle.exclamation) stunumtxtbox.select() end if as rule, exceptions should not used input validations. never use try...catch things can test in other simple ways.
one last thing: loop redundant. if have 1 row, there no need loop.
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