Can't change border color of Material-UI OutlinedInput

Question

I'm trying to change the border color of a v4.13 MaterialUI Outlined Input. However I have not gotten anything to work when trying to override the CSS.

I've tried multiple CSS rules applied to each element, the select and the OutlinedInput, with the two below being the most recent. What am I doing wrong here?

const styles = () =>
  createStyles({
    select: {
      "&:before": {
        borderColor: "red"
      },
      "&:after": {
        borderColor: "red"
      },
    },
    outline: {
      "&:before": {
        borderColor: "red"
      },
      "&:after": {
        borderColor: "red"
      },
    }
  });

   <Select
      label={label}
      fullWidth={true}
      error={touched && invalid}
      className={inputStyles}
      classes={{ root: classes.select }}
      input={
        <OutlinedInput
          {...input}
          fullWidth={true}
          id={input.name}
          labelWidth={this.state.labelWidth}
          classes={{notchedOutline: classes.outline}}
        />
      }
      {...custom}
    >
      {children}
    </Select>

I can see here where the border-color is being set, but am unable to override it.

Answer 1

Here's an example showing how to do this in v4 (v5 example further down):

import React from "react";
import { makeStyles } from "@material-ui/core/styles";
import OutlinedInput from "@material-ui/core/OutlinedInput";
import InputLabel from "@material-ui/core/InputLabel";
import MenuItem from "@material-ui/core/MenuItem";
import FormControl from "@material-ui/core/FormControl";
import Select from "@material-ui/core/Select";

const useStyles = makeStyles(theme => ({
  root: {
    display: "flex",
    flexWrap: "wrap"
  },
  formControl: {
    margin: theme.spacing(1),
    minWidth: 120
  },
  selectEmpty: {
    marginTop: theme.spacing(2)
  }
}));
const useOutlinedInputStyles = makeStyles(theme => ({
  root: {
    "& $notchedOutline": {
      borderColor: "red"
    },
    "&:hover $notchedOutline": {
      borderColor: "blue"
    },
    "&$focused $notchedOutline": {
      borderColor: "green"
    }
  },
  focused: {},
  notchedOutline: {}
}));

export default function SimpleSelect() {
  const classes = useStyles();
  const outlinedInputClasses = useOutlinedInputStyles();
  const [values, setValues] = React.useState({
    age: "",
  });

  const inputLabel = React.useRef(null);
  const [labelWidth, setLabelWidth] = React.useState(0);
  React.useEffect(() => {
    setLabelWidth(inputLabel.current.offsetWidth);
  }, []);

  function handleChange(event) {
    setValues(oldValues => ({
      ...oldValues,
      [event.target.name]: event.target.value
    }));
  }

  return (
    <form className={classes.root} autoComplete="off">
      <FormControl variant="outlined" className={classes.formControl}>
        <InputLabel ref={inputLabel} htmlFor="outlined-age-simple">
          Age
        </InputLabel>
        <Select
          value={values.age}
          onChange={handleChange}
          input={
            <OutlinedInput
              labelWidth={labelWidth}
              name="age"
              id="outlined-age-simple"
              classes={outlinedInputClasses}
            />
          }
        >
          <MenuItem value="">
            <em>None</em>
          </MenuItem>
          <MenuItem value={10}>Ten</MenuItem>
          <MenuItem value={20}>Twenty</MenuItem>
          <MenuItem value={30}>Thirty</MenuItem>
        </Select>
      </FormControl>
    </form>
  );
}

You can read more about this in my related answers:

• Change outline for OutlinedInput with React material-ui
• Global outlined override
• Change border color on Material-UI TextField

---

Here's a similar example, but for v5 of Material-UI using styled:

import React from "react";
import { styled } from "@material-ui/core/styles";
import { outlinedInputClasses } from "@material-ui/core/OutlinedInput";
import InputLabel from "@material-ui/core/InputLabel";
import MenuItem from "@material-ui/core/MenuItem";
import FormControl from "@material-ui/core/FormControl";
import Select from "@material-ui/core/Select";

const StyledForm = styled("form")(`
  display: flex;
  flex-wrap: wrap;
`);
const StyledFormControl = styled(FormControl)(({ theme }) => ({
  margin: theme.spacing(1),
  minWidth: 120
}));
const StyledSelect = styled(Select)(`
  & .${outlinedInputClasses.notchedOutline} {
    border-color: red;
  }
  &:hover .${outlinedInputClasses.notchedOutline} {
    border-color: blue;
  }
  &.${outlinedInputClasses.focused} .${outlinedInputClasses.notchedOutline} {
    border-color: lime;
  }
`);

export default function SimpleSelect() {
  const [values, setValues] = React.useState({
    age: ""
  });

  function handleChange(event) {
    setValues((oldValues) => ({
      ...oldValues,
      [event.target.name]: event.target.value
    }));
  }

  return (
    <StyledForm autoComplete="off">
      <StyledFormControl variant="outlined">
        <InputLabel id="outlined-age-simple-label">Age</InputLabel>
        <StyledSelect
          labelId="outlined-age-simple-label"
          value={values.age}
          onChange={handleChange}
          name="age"
          label="Age"
        >
          <MenuItem value="">
            <em>None</em>
          </MenuItem>
          <MenuItem value={10}>Ten</MenuItem>
          <MenuItem value={20}>Twenty</MenuItem>
          <MenuItem value={30}>Thirty</MenuItem>
        </StyledSelect>
      </StyledFormControl>
    </StyledForm>
  );
}